Prenatal multi dha side effects


How to Deal with Prenatal Vitamin Side Effects

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Women in their first trimester of pregnancy are most likely to experience morning sickness—a symptom compounded by the fact that prenatal vitamins can cause nausea too. Which leaves some queasy-stomached moms-to-be wondering, How bad is it if I occasionally skip my prenatal?

  • Related: How to Choose the Best Prenatal Vitamins for You

Although expectant women with very healthy eating habits may be able to forgo their vitamin here and there without major ramifications, it’s better to find a way to make supplements more palatable, says Miriam Erick, a senior perinatal dietitian at Brigham and Women’s Hospital in Boston and the author of No More Morning Sickness: A Survival Guide for Pregnant Women.

Try taking your daily supplement with something slippery you can stomach, like applesauce, suggests Erick. Never take your vitamin on an empty stomach, which can worsen nausea. “You can also try taking vitamins with lemonade or one of what I call the ‘friendly’ juices: creamy, smooth juice drinks like an orange-banana combo,” Erick says. Just make sure it doesn’t contain added sugar.

A third option is to take your supplement at a different time of day. Some women have the best luck at night, Erick says. Or try cutting it in two and taking half in the morning and half at night.

Or try another brand: vitamins vary in size, smell, and taste, and one brand might go down easier than another. “I always tell patients ‘Buy a small quantity. Try them. See how you feel. Make sure you’re not burping up fish and it’s not killing your day, and then continue,'” says Julie Levitt, M.D., an ob-gyn at Women’s Group of Northwestern in Chicago.

As a last-ditch effort, Erick advises trying kids’ chewable vitamins with folic acid, a crucial vitamin for fetal brain and spine development. “Although they have lower dosages,” she says, “something is better than nothing.”

  • Related: The Benefits of Folic Acid

Taking too much of a particular vitamin can cause serious side effects, but it’s rare if you’re otherwise maintaining a healthy diet. “There’s not much risk in over-supplementing, per se, because a lot of these are fat-soluble vitamins, so they just go into your stores; they don’t poison the baby,” says Dr. Levitt.

But (and this is a big but) there are a few vitamins that you definitely don’t want to overdo it on—chiefly vitamin A, which can cause birth defects in high levels. Avoid supplements with more than 100 percent of the recommended dietary allowance of vitamin A, says Dr. Levitt. Most women won’t get near a toxic amount, but watch out for other supplements or herbal remedies, which could contain vitamins that aren’t listed under a name you’d recognize, says Scott Sullivan, M.D., the director of maternal-fetal medicine at Medical University of South Carolina.

Additionally, some studies have linked excessive folic acid to asthma, heart problems, cancer, and ectopic pregnancy. A 2014 study published in the Journal of Epidemiology & Community Health found that women who took folic acid supplements were twice as likely to die of breast cancer. Some women have a harder time absorbing the synthetic folate, or folic acid, found in prenatal vitamins, which may increase their risk of miscarriage.

You need a vitamin you’re comfortable with since you won’t necessarily stop taking it after your baby arrives. Most doctors advise continuing on prenatal vitamins for the duration of breastfeeding, or longer if you want to have another baby soon. When in doubt, ask your doctor about your prenatal vitamin and any other supplements you’re taking.

  • By Diana McKeon Charkalis


Best Prenatal Vitamins of 2020

You already know that good nutrition is important during pregnancy.

That’s why your shopping cart looks like a rainbow, and you’re planning meals with all the food groups. But let’s be honest: it’s hard to know if you’re really getting all the vitamins and minerals you and your baby need.

That’s where prenatal vitamins come in. They don’t replace a balanced diet, but instead act like backup—making sure you don’t fall short on the essential nutrients you need during pregnancy.

In this article:

  • Babylist’s Picks for Best Prenatal Vitamins
  • Do You Need Prenatal Vitamins?
  • When Should I Start Taking Prenatal Vitamins?
  • How Do I Choose Prenatal Vitamins?

Do You Need Prenatal Vitamins?

A run-of-the-mill multivitamin won’t cut it when you’re pregnant. Prenatal vitamins are specially designed multivitamins that deliver the extra amounts of nutrients needed during various stages of your baby’s development. For example, they contain folic acid, which is important for baby’s brain development in the earliest stages. And many have vitamin D and calcium to build strong bones and teeth during the third trimester of pregnancy.

Plus, prenatal vitamins help make sure you have enough nutrients such as iron, to not only provide to your baby but so your own body doesn’t become depleted.

When Should I Start Taking Prenatal Vitamins?

Ideally, you should start taking prenatal vitamins at least a month before conception and throughout your entire pregnancy from 4 weeks pregnant to whenever labor and birth starts. In fact, it’s often best to take a prenatal vitamin every day if there’s a chance you could get pregnant at all, even if you’re not planning for it. That’s because crucial neurological development takes place during the first month of pregnancy, when folic acid would offer the most protective benefits. (If you are trying to conceive and think you might be pregnant, check out our guide to the best pregnancy tests.)

If you’re already pregnant and haven’t been taking prenatal vitamins, no need to worry! Just start as soon as you can.

How Do I Choose Prenatal Vitamins?

Prenatal vitamins are readily available over the counter and a prescription is generally unnecessary. (Note: check with your insurance to see if they cover prenatal vitamins. If so, you’ll likely need your doctor to give you a prescription for them.)

Every vitamin can differ in the types and amounts of nutrients it contains because specific vitamin ingredients aren’t regulated by the FDA. If the vitamin you choose doesn’t contain the full recommended daily amount of a nutrient, be sure to eat foods that are high in that vitamin or mineral.

When shopping for prenatal vitamins look for these four primary nutrients that are especially important during pregnancy (amounts are per day and recommended by the American College of Obstetricians and Gynecologists):

  • Folic acid: 600 mcg
  • Iron: 27 mg
  • Calcium: 1,000 mg (note: most prenatal vitamins don’t contain this much calcium, so you if don’t get enough from your diet, talk to your doctor about taking a separate calcium supplement)
  • Vitamin D: 600 IU

The following vitamins are also essential during pregnancy, and you may not get enough of them through diet alone. Having these in your prenatals are helpful too:

  • Vitamin A: 770 mcg (Note: The safest form of Vitamin A is beta-carotene or other carotenoids.)
  • Vitamin C: 85 mg
  • Vitamin B6: 1.9 mg
  • Vitamin B12: 2.6 mcg

Consider it a bonus if you find a prenatal vitamin that also contains omega-3 fatty acids. There’s strong evidence indicating that omega-3 fatty acids (particularly DHA)–a fat found in some types of fish–may play an important role in the development of your baby’s brain and nervous system. The March of Dimes recommends you get 200 mg of DHA a day through diet or supplementation.

Vitamins come in multiple forms: pill, soft-gel capsule and gummies. For some, swallowing and holding down a pill can be difficult especially when you’re queasy due to morning sickness. If that’s your situation, try a soft-gel capsule or a gummy vitamin. Note: gummy vitamins do not contain iron, so you’ll want an extra iron supplement for that.

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Best Prenatal Vitamins

To make shopping for prenatal vitamins easier, we found several winning options for you to consider.

Best Budget Prenatal Vitamin

If you’re watching your wallet, Nature Made prenatal vitamins are a great value. Not to mention, you can probably find them at your local drugstore. They provide your full quota of folic acid, iron and vitamin D as well as other essential vitamins.

The Nature Made prenatals even contain the full recommended amount of DHA (great if you don’t regularly eat fish). The bonus? You only have to take one soft gel capsule a day.

Keep in Mind

These Nature Made vitamins are skimpy on calcium, with only 150 mg. If you don’t get enough calcium between that and your diet, you may need a supplement that has more of this vital nutrient.

Best Prenatal Gummy Vitamins

Okay, real talk: swallowing anything, and keeping it down, can be a major challenge for some moms-to-be. But some swear that vitamin gummies do the trick.

Smarty Pants gummy vitamins come in lemon, orange and strawberry-banana flavors and have zero artificial colors, sweeteners, preservatives or high fructose corn syrup. You’ll need to eat six a day to get the amount of folic acid and vitamin D required for pregnant women. And you’ll even get a bit of DHA too (48 mg).

You won’t get iron from any gummy vitamin, but this one also lacks calcium. Ask your doctor if an additional supplement is necessary to get the iron and calcium needed during pregnancy.

Best Prenatal Vitamins with DHA

If you’re looking to up your intake of DHA during your pregnancy, this prenatal is a good supplement. With 480 mg of DHA per serving, it surpasses daily intake recommendations of omega-3s for baby’s brain development.

It’s also certified to be free of environmental toxins, including heavy metals, and has earned a seal of approval by NSF International (a third party that tests supplements for quality and safety).

This isn’t a prenatal multivitamin—it’s a DHA supplement. Though it does contain 400 I.U. of vitamin D3 in addition to the DHA, if you’re looking for iron, folic acid or other vitamins and minerals, you should take this in addition to a regular prenatal.

Best Natural Prenatal Vitamins

Sure, MegaFood vitamins are pricey, but there’s a good reason why. This brand has an independent seal of approval by NSF International, a third party that verifies supplements meet high quality and safety standards.

Unlike other brands that use less-expensive but harder-to-absorb ingredients, Baby & Me is loaded with “food state” nutrients—in other words, they’re naturally derived from foods (many of which are organic), which makes them easy for your body to actually use. You get the perfect amount of vitamin D and more than enough folic acid by taking the recommended four pills a day.

You need 27 to 30 mg of iron a day when you’re pregnant, but Baby & Me only contains 18 mg. Also, this supplement only provides 6% of your recommended daily calcium. So, you’ll need to make sure you’re eating plenty of iron and calcium rich foods too.

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Best Prenatal Vitamins with Iron

A spoonful of sugar may help the medicine go down, but the Honest Co. uses a coating of natural vanilla instead to make their once-a-day prenatals easier to swallow. Digestive enzymes derived from pineapple, papaya and kiwi, plus ginger and B6, help the pills better settle in a sensitive stomach too.

These prenatals are full of vitamin D, iron and folic acid, as well as spirulina. They have many organic ingredients, and they can even be taken on an empty stomach.

These vitamins also fall shy of the daily calcium requirement for pregnancy, with only 150 mg. But if you regularly drink milk or eat yogurt, that could be a non-issue for you.

Best Prenatal Vitamins with Folate/Folic Acid

If you’re all about knowing where your food comes from, you’re going to love these vitamins. Ritual not only specifies the exact form of their vitamins and minerals (since there can be more than one option), but also where each nutrient is sourced.

These prenatals contain an abundance (1,000 mcg) of folate (the naturally occurring form of folic acid) from Italy, DHA from Canada and vitamin D3 from the United Kingdom, as well as other vitamins and minerals. And for sensitive stomachs, the two capsules a day are designed not to dissolve until they reach an area of your digestive tract that’s less likely to trigger nausea.

These supplements lack calcium, and although they have 18 mg of iron, they don’t meet the daily requirement. You’ll have to be focused on getting plenty of those key nutrients through your diet instead. And the price indicates a monthly subscription.

Best Liquid Prenatal Vitamins

Liquid prenatal vitamins may be a good choice if you’re having a tough time swallowing pills and you’re not into gummies. (Though they do have a flavor that not everyone loves.) The Pink Stork liquid contains 100% or more of the daily recommendation for many important nutrients. It’s gluten-free, non-GMO and contains no animal products. Plus, it claims its 18 mg of iron are non-constipating. May be worth a try!

You may need a calcium supplement, since this liquid only contains 20 mg of the nutrient. It also comes in a traditional capsule form.

Best Prenatal Vitamins Without Iron

As we mentioned before, iron can be constipating, and it can upset some people’s stomachs. If that sounds like you, this GNC vitamin may be worth trying. While it’s lacking in iron, it still has lots of folic acid (1,000 mg) and a decent amount of calcium (600 mg) and vitamin D (400 IU).

If you’re not tolerating iron well, talk to your doctor before switching to a prenatal vitamin without iron. They may suggest other solutions that don’t mean skipping this important mineral.

Best Gentle Prenatal Vitamins

The thought of taking a prenatal vitamin when you’re struggling with morning sickness can make your stomach turn even more. This prenatal from New Chapter may be gentler on you, thanks to the addition of ginger. It’s also certified organic, vegetarian, non-GMO, gluten free and Kosher, and has a lot of the vitamins and minerals you want, including folate and iron (the iron also is fermented to also gentler on your system).

There’s no DHA in this one, and there’s only a little bit of calcium, so you’ll want to take additional supplements.

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Choosing What’s Right For You

When thinking about which prenatal vitamin to buy, consider what you typically eat and where your diet may fall short. If you’re a vegetarian, iron supplementation might be crucial. If you don’t eat dairy, calcium might be a must-have. Hate fish? Then look for a vitamin that contains DHA.

If you still feel unsure about which prenatal vitamin is best for you, ask your doctor for a recommendation. You’ll rest easier knowing you’re taking a supplement that helps your body keep up with the increased demands of pregnancy.

The Effect of Omega-3 Docosahexaenoic Acid Supplementation on Gestational Length: Randomized Trial of Supplementation Compared to Nutrition Education for Increasing n-3 Intake from Foods


Objective. DHA supplementation was compared to nutrition education to increase DHA consumption from fish and DHA fortified foods. Design. This two-part intervention included a randomized double-blind placebo controlled DHA supplementation arm and a nutrition education arm designed to increase intake of DHA from dietary sources by 300 mg per day. Setting. Denver Health Hospitals and Clinics, Denver, Colorado, USA. Population. 871 pregnant women aged 18–40 were recruited between16 and 20 weeks of gestation of whom 564 completed the study and complete delivery data was available in 505 women and infants. Methods. Subjects received either 300 or 600 mg DHA or olive oil placebo or nutrition education. Main Outcome Variable. Gestational length. Results. Gestational length was significantly increased by 4.0–4.5 days in women supplemented with 600 mg DHA per day or provided with nutrition education. Each 1% increase in RBC DHA at delivery was associated with a 1.6-day increase in gestational length. No significant effects on birth weight, birth length, or head circumference were demonstrated. The rate of early preterm birth (1.7%) in those supplemented with DHA (combined 300 and 600 mg/day) was significantly lower than in controls. Conclusion. Nutrition education or supplementation with DHA can be effective in increasing gestational length.

1. Introduction

Evidence from both human and animal studies suggests that essential fatty acids of the n-6 and n-3 series play important and modifiable roles in maintaining gestation. In early epidemiological studies erythrocyte (RBC) n-3 docosahexaenoic acid (DHA) correlated with gestational age. Previous studies in our laboratory have shown that women delivering prematurely had markedly decreased n-3 DHA and elevated n-6 arachidonic acid (ARA) and n-6 linoleic acid (LA) pools in both RBC membranes and plasma phospholipids and increased RBC membrane n-6 docosapentaenoic acid (DPA), a biomarker for n-3 fatty acid insufficiency . In an early randomized supplementation trial, pregnant women supplemented with 2.7 g EPA + DHA/day throughout the second half of gestation experienced a significant 4.5-day increase in gestational length . A food based supplementation trial in pregnant women demonstrated that 137 mg of DHA per day from 24–28 weeks until delivery increased gestational length by a significant days . The FOTIP trials of fish oil supplementation in high risk pregnancy demonstrated a reduction in the recurrence of preterm birth from 33% to 22%, OR .54 (95% CI, 0.30, 0.98), and resulted in an 8.5-day increase in gestational length and significant increases in infant birth weight. A recent report demonstrated that supplementation with 600 mg/day DHA from the 20th week of pregnancy resulted in a 2.9-day increase in gestational length accompanied by increased birth weight, length, and head circumference reduction in preterm birth at <34 weeks . However, results from randomized controlled trials remain inconclusive . Several meta-analyses failed to show any effects of DHA or fish oil supplements on gestational length and birth weight . Data from the maternal-fetal network trials of 17-hydroxy progesterone and fish oil for the prevention of preterm birth were unable to show an additive effect of high doses of fish oil on reduction in the recurrence of preterm birth . However, an examination of fish intake in this group showed that intake of moderate amounts of seafood was associated with increased gestational length . Overall, the effect of fish intake on reduction in preterm (PT) birth has been more consistent than the effect of fish oil or DHA supplements and questions about the effect of DHA supplementation in pregnancy outcomes remain unanswered. Therefore, specific objective of this study was to compare supplementation at two levels of DHA oil to nutrition education targeted to increase DHA consumption from fish and DHA fortified foods on gestational length.

2. Methods

The study was a two-part intervention which included a randomized double-blind placebo controlled supplementation arm in which subjects received either 300 or 600 mg of algal derived DHA or olive oil placebo and a nutrition education arm designed to increase intake of DHA by 300 mg per day from fish and other dietary sources. Approval was obtained from the Human Research Committee of Colorado State University and Colorado Multiple Institutional Review Board.

2.1. Subjects

The sample size was determined on the basis of the number of subjects needed to detect a 5-day difference in gestational age at the level. 871 subjects were recruited from Denver Health Hospitals (Denver, CO) antenatal clinics. Four of the largest clinics were selected to participate in the study. Three clinics were randomized to receive supplements and one to receive nutrition education. For the supplemental arm, 662 subjects were recruited and of these 28 were ineligible, 634 subjects were randomly allocated to treatment, 289 withdrew, and complete delivery data was available on 345 subjects in the supplemental arm. 209 subjects were recruited and consented to participate in nutrition education. Birth data was available on 191 of these and 18 were lost to follow-up. In total, complete delivery data was available for 536 of the 563 subjects (Table 1). Baseline demographic and anthropometric characteristics of subjects (Table 2) in the four groups were not significantly different and there were no differences in between those who completed the study and those who withdrew. Patients were enrolled during regularly scheduled prenatal visits at 16 to 20 weeks of gestation or at WIC intake visits. Subjects with singleton pregnancies were eligible for the study if they were 18 years of age or older, willing to participate, and able to sign informed consent and HIPPA forms in English or Spanish. Subjects were excluded from the study if they presented with known medical or obstetrical complications associated with increased risk for preterm birth including cervical incompetence, presence of cervical cerclage, placenta previa, intrauterine infection, known substance abuse, multiple fetuses, current preeclampsia, preexisting diabetes, or a history of gestational diabetes in a prior pregnancy. Subjects were also excluded if they were taking nonsteroidal anti-inflammatory drugs (NSAIDS) or if they consumed salmon, mackerel, rainbow trout, or sardines at least once weekly or if they had known allergies to fish or any constituent of the nutritional supplement.

Table 1 Subject characteristics by group and comparison of those who completed study and those who withdrew from study. Table 2 Race and ethnicity of subjects by group and completion status.

2.2. Supplemental Arm

Subjects were recruited by study professional research associates and allocated to one of three treatment groups (300 mg DHA, 600 mg DHA, or placebo) using a stratified block randomization schedule, generated using a randomization table by staff at Martek Biosciences, to insure equal group assignment from each of three clinics participating in the supplement trial. DHA was provided in the form of 300 Kcal supplement bars containing DHASCO-S oil. Gel capsules containing the test oil or olive oil were available for those who refused the bars. Bars and gel capsules were provided by Martek Biosciences, Columbia, MD. Supplementation was initiated at week 20 of gestation and continued until delivery. Both subjects and all study personnel were blinded as to treatment. DHA content of the bars and capsules was verified by gas chromatography. Table 3 contains fatty acid analysis of the DHASCO-S oil. Compliance was determined from return of study bars or capsules at regularly scheduled intervals and after delivery at the first postnatal visit and averaged 76–81%.

Table 3 Fatty acid composition of DHASCO-S oil.

Prepackaged supplements were stored in cool secured locations, accessible only to the investigative team. A four- to six-week supply of supplements was dispensed at each prenatal visit and subjects were instructed to return any unused supplements. Records of the supplements dispensed and returned were used to calculate adherence with treatment. In addition, each subject kept a supplement diary and research assistants reviewed supplement diaries at each prenatal visit and collected data on side effects, dietary intake of DHA-rich foods, and adverse events including vaginal infections, vaginal bleeding, and preterm labor occurring during pregnancy. Following delivery, maternal and infant medical records were reviewed for adverse antenatal and intrapartum events in the supplemental arm. The maternal record provided date of delivery, estimated delivery date, maternal height and weight at first prenatal visit, mode of delivery, type of rupture of membranes (ROM), type of labor onset, estimated blood loss, and complications of labor and delivery. The newborn record provided information on infant gender, birth weight, birth length, and head circumference. Gestational length was determined using the difference between the estimated delivery date and the actual delivery date. Gestational length was determined using the difference between the delivery date established using a combination of the LMP method and ultrasound, where available, and the actual delivery date.

2.3. Erythrocyte DHA Levels

Blood samples were obtained at enrollment between 16 and 20 weeks of gestation and at delivery. Seven mL blood samples were drawn in EDTA-containing vacutainer tubes. Samples were separated by centrifugation (1600 g, 10–15 min at 25°C) within four hours of delivery and flushed with nitrogen gas, frozen in liquid nitrogen, and stored at −80°C for later batched analysis of phospholipid fatty acids. Plasma lipids were extracted in chloroform/methanol (2 : 1 v : v). Fatty acid methyl esters (FAME) will be prepared by transmethylation with 14% boron trifluoride in methanol (Sigma Chemicals, St Louis, MO). FAME were analyzed by temperature-programmed gas liquid chromatography using a 30 m × 0.25 mmID microcapillary column and identified using reference standards (Nu-Check Prep, Elysian, MN).

Dietary intake of long chain n-3 fatty acids was estimated at enrollment (16–20 weeks), using a pictorial food frequency inventory developed for this study. The food frequency was validated against RBC DHA in 340 subjects shown in Figure 1 (, ). The inventory contained a finite list of foods which are the rich sources of long chain n-3 fatty acids (≥1.0 mg/100 g edible portion of DHA +/or EPA) and DHA-enriched functional foods and eggs. The food inventory was quantitated using the USDA Nutrient Data Base (release 15).

Figure 1 Validation of food frequency inventory with erythrocyte (RBC) membrane percent total DHA.

Nutrition Education Intervention: subjects were recruited from a fourth Denver Health, Women Infants and Children’s (WIC) clinic, which was not participating in the clinical trial to avoid contamination of the supplemental groups by nutrition information. Convenience sampling was used to recruit subjects at WIC clinic visits between 18 and 20 weeks of gestation to participate in the nutrition education component of the study. Subjects received educational materials which were developed using focus group data collected in this population and based upon the Health Belief Model. This process and resulting materials are described elsewhere . The education materials included a daily reminder/planner with DHA information, a refrigerator magnet, shopping lists, recipes, recipe holders, and personalized stickers for use in the daily planner. Materials also included a short (one-page) printed nutrition education flyer discussing the benefits of omega-3 fatty acids. Each month, participants received a mailing that included additional recipes and DHA-enriched egg coupons. A choice of several cans of DHA-rich fish (albacore tuna, sardines, and pink salmon) was given to each participant at the time of enrollment. Adherence to nutrition education was established by tracking egg coupon redemption over time and by follow-up telephone interviews of participants. An average of 11 dozen egg coupons per participant were redeemed which represented availability of 6 eggs per subject per week.

2.4. Statistical Analysis

The primary outcome variables tested were gestational length (in days). Secondary outcomes, infant birth weight, birth length and head circumference, percent preterm birth, and percent postterm birth were evaluated. Continuous variables were analyzed using analysis of covariance (ANCOVA) and regression analysis using the SAS statistical package version 14. An intent to treat analysis was conducted using SAS phreg and lifetest procedures. Covariates used in the ANCOVA, maternal prepregnancy BMI, and ethnicity were those shown to have significant effects on gestational days in the univariate analysis. Dichotomous variables were analyzed using the IBM SPSS Statistics 20, Pearson Chi-Square analysis.

3. Results

To examine the difference in effectiveness of DHA supplements in the form of gel capsules compared to the food bars, analysis of differences in gestational length by supplement type was conducted. Fifty-one subjects consumed capsules as a substitute for bars. There was no difference in response within each group attributable to supplement type (). The intent to treat analysis showed that there were no significant differences in ethnicity or other characteristics of those who completed the study compared to those who withdrew (Table 1). Ethnicity by group in those who completed and withdrew is shown in Table 3. The population was 78.5% Hispanic and did not vary between those who completed and withdrew from the study. However, because ethnicity varied among treatment groups and gestational length and birth weights of Hispanic babies were higher than all others, ethnicity was used as a control variable in the ANCOVA of gestational length and birth weight. Gestational length, birth weight, birth length, and head circumference are shown in Table 4. There was a significant ( for the model) 4-day increase in gestational length with 600 mg ( DHA supplement) and 4.5 days with nutrition education () compared to controls (Table 4). There was a 4-day increase in gestational length with the 300 mg supplement which approached significance (). The differences between 600 mg DHA supplement and nutrition education groups were not significant.

Table 4 Birth weight and gestational age by intervention group1 (mean ± sem).

Four infants were born postterm (>294 days), one in each of the supplement groups and two in the nutrition education group. Labor was induced at 41 weeks in thirteen subjects, four supplemented subjects (all in the 300 mg DHA group) compared to six in the placebo and three in the education group (Table 4). There were no significant increases in the total number of subjects who had induced labor at any gestational age nor any differences in parity among supplementation groups (Table 5). Fifty-one infants (9.5%) were born preterm (<280 days) and there were no significant differences among groups. Fourteen infants were born at less than 34 weeks of completed gestation, two in each of the DHA groups (1.7%), three in the nutrition education group (1.8%), and seven (5.7%) in the placebo group. These rates were not found to be significantly different by Chi-square analysis (). In order to test the effect of any amount of DHA in the controlled trial, 300 and 600 mg DHA treatment groups were combined. When supplement groups were combined, the preterm birth rate in those receiving any DHA (300 or 600 mg/day) was not significantly different from placebo. The early preterm birth rate of 1.7% in those supplemented with any DHA (300 or 600 mg/day) was significantly lower than the early preterm birth rate of 5.7% in the placebo group ( by two-tailed Chi-square analysis).

Table 5 Selected preterm birth risk factors in supplemented subjects in 129 control, 124 supplemented with 300 mg DHA, and 116 supplemented with 600 mg DHA (mean ± 1 sem).

Mean birth weight, birth length, and head circumference with supplementation or nutrition education did not differ from the control or among groups. Maternal RBC DHA significantly increased in supplemented groups and decreased in controls. Maternal RBC % total DHA at delivery positively correlated with gestational length () and birth weight (). Each 1% increase in RBC DHA was associated with a corresponding 1.6-day increase in gestational length. Maternal RBC % total arachidonic acid at delivery was not correlated with gestational length or birth weight.

Dietary DHA intake among Non-Hispanic Whites averaged 69 mg/day, African American 161 mg/day, Hispanics 143 mg/day, and others 119 mg/day. In those who completed the study, adherence to supplement ranged from 75% to 80% and did not significantly differ among groups.

RBC membrane DHA levels in the supplemented groups (expressed as percent total fatty acids) were not significantly different at entry (Table 1). Mean DHA levels (±SD) were significantly increased at delivery with either the 300 mg or 600 mg supplement ( and , resp.) compared to CON ().

Given the broad inclusion criteria and the potential for pregnancy complications from altering maternal fatty acid consumption, we recorded and analyzed a large variety of adverse effects. The most serious of these included late miscarriage, stillbirth, and early neonatal demise and each of these is due to extreme immaturity at delivery. In each of these cases, delivery occurred after enrollment but before consumption of supplements. In each instance women removed themselves from the study and were thus included only in the “intent to treat” analysis. Other obstetrical outcomes included cervical insufficiency, primary intra-intrauterine infection, placenta previa necessitating expedited surgical delivery, and an undiagnosed uterine anomaly and were deemed not to be study related. There were only 3 cases of severe preeclampsia (1 in each group of the supplement arm) and a very low incidence of postpartum bleeding and no difference in blood loss among supplementation groups. Events at delivery (Table 6) including premature rupture of membranes (PROM), preterm premature rupture of membranes (PPROM), spontaneous rupture of membranes (SROM), and augmented rupture of membranes (AROM) and type of labor were analyzed in the supplement arm. Supplementation showed no significant negative effects of DHA supplements.

Table 6 Delivery events in supplemented subjects in 129 control, 124 supplemented with 300 mg DHA, and 116 supplemented with 600 mg DHA (%).

4. Discussion

The data are in agreement with several studies of fish oil supplementation at higher doses in which average 4- to 4.5-day increases in gestational length were observed . It is probable that there a ceiling effect exists at about 600 mg DHA/day. The increase in gestational length in this study with 600 mg/day or nutrition education was lower than the 6-day increase demonstrated in a small study in which subjects were supplemented with 165 mg of a food source of DHA but comparable to a study with 600 mg of the identical source of supplemental DHA, which reported a 2.9-day increase in a similar number of subjects . This difference may be attributable to the relatively low risk for preterm delivery and low birth weight in the Hispanic population compared with a different ethnic composition of the low income population or the relatively small number of subjects in the former food based study. Alternatively, it is possible that food based DHA has a greater effect on gestational length, although that was not evident comparing our food based nutrition education group to supplements in this study.

To date, two systematic analyses did not show a statistically significant effect of n-3 supplements using combined power of several studies on gestational length, reduction of PT labor, birth weight, or birth length. However, a meta-analysis which included four studies, three of which used long chain fatty acids, showed a significant decrease in early preterm birth (<34 weeks) and no decrease in late preterm birth . An earlier meta-analysis of six studies demonstrated a nonsignificant increase in gestational length, birth weight, birth length, and risk for PT birth or low birth weight, but some question remains since the data from one study was entered using the unadjusted increase in gestational length of 2.4 days not 6 days as published in the original report. The decrease in the incidence of preterm birth at <34 weeks in 350 women supplemented with 600 mg DHA/day from week 20 of gestation to delivery recently confirmed this effect . A large Australian study which supplemented 2320 pregnant women with 800 mg DHA/day as fish oil from 20 weeks of gestation to delivery reaffirmed a decrease in risk for early preterm birth (adj OR .49, 95% CI, .56, 1.04) and found a significant () 68 g increase in birth weight corresponding to a one-day increase in gestational length with the DHA supplement . This increase in birth weight was similar to that seen in this study (46–56 g) with 300 and 600 mg DHA/day supplements, although the increase was not significant due to the smaller number of subjects.

Although some differences in DHA intake among Hispanics and non-Hispanic Whites and African American subjects were seen in this study population, intakes were similar to those previously reported. The 2007-2008 National Health and Nutrition Examinations Survey (NHANES) and What We Eat In America (WWEIA) show that women aged 20–29 years consume 0.05 grams (50 mg) DHA/day from food sources and women aged 30–39 years consume on average 0.06 grams (60 mg) DHA/day . Judge used multiple 24-hour dietary recalls to measure baseline DHA intake of pregnant women in Connecticut and found that the average intake was 80 mg/day . Chen et al. observed a range of 50–90 mg DHA/day intake among pregnant women with gestational diabetes mellitus living near New Jersey . Among 20–40-year-old pregnant women from Canada, Friesen and Innis found that the mean DHA intake was 100 mg/day at 36 weeks of gestation . Intakes are much lower than consensus recommendations for 200 mg DHA/day during pregnancy . As previously reported, supplementation with DHA prevented the decrease in maternal DHA stores and increased maternal RBC DHA at 36 weeks which we have previously correlated with decreased risk for preterm birth .

Overall, small to moderate fish consumption has a greater impact on preterm delivery than fish oil supplements. Studies of FO supplementation had greatest effects on women who eat little or no fish and tend to have no effect on gestational length in women with high baseline intakes of fish. FO or DHA supplements may not fully take the place of eating fish . In the maternal-fetal network study, moderate fish intake decreased risk for reoccurrence of preterm birth, although the fish oil supplement did not. One reason may be that fish contain Vitamin D. Vitamin D deficiency has been associated with an increased risk for PT delivery . Fish contain DHA, Vitamin D, and other nutrients which may be more effective than FO or DHA alone in reducing preterm delivery and promoting optimum neurocognitive development. For this reason, the 2010 Dietary Guidelines for Americans recommend that pregnant and breastfeeding women consume 8 to 12 ounces of fish per week .

4.1. Strengths and Limitations

The physiological significance of a 4-day increase in gestational length is unknown. However, a four-day increase may have a great impact on long term outcomes since recent data suggests birth between 37 and 38 completed weeks of gestation is associated with a 10% greater risk for attention-deficit hyperactivity disorder (ADHD) in school age children which increases to 30% in those born between 35 and 36 weeks of gestation . Limitations of the study include the convenience sampling and nonblinded design of the nutrition education arm. This group, randomized only by clinic, may have impacted the result in that individuals that were more highly motivated by maternal nutrition may have volunteered to receive the education.

Another limitation was that baseline blood DHA levels and obstetric risk factors were not obtained in the nutrition education arm and these may have affected the outcome. However, there were no differences in initial RBC DHA levels or significant differences in demographics or obstetrical variables among any of the other three clinics serving the same population nor were there initial differences among treatment groups. Comparison of early preterm birth rates was only significant when the treatment groups were pooled. This result should be regarded with caution since the number of early preterm births was small and these were not preplanned comparisons. The strength of the study is that the effects of n-3 DHA from supplements and from food sources on gestational length were comparable in the same population group. Although the population studied was low income, the subjects were largely Hispanic, a group known to be at lower risk for preterm birth compared to other low income groups, so the results may not be generalizable to other populations.

5. Conclusions

Nutrition education or supplementation with DHA was shown to be effective in increasing gestational length in a low income population at relatively low risk for preterm birth. Improving DHA status through education or supplements is vital since maternal DHA levels are correlated with fetal DHA status and also represent enhanced DHA stores to support lactation and early infant growth and cognitive development. The nutrition intervention in this study would be expensive for clinics to implement but WIC programs routinely provide nutrition education at 3-month intervals to low risk pregnant participants and more frequently to high risk participants. Many WIC programs currently offer omega-3 DHA counseling and some even offer DHA-enriched foods. Alternative education methods may be explored, including existing programs such as Text4Baby which delivers gestational age appropriate health messages to pregnant and postnatal subscribers.

Conflict of Interests

None of the authors have conflict of interests to disclose.

Authors’ Contribution

Mary A. Harris, James A. McGregor, Kenneth G. D. Allen, Jennifer E. Anderson, and Garry W. Auld all participated in the inception, planning, and carrying out of the study. Janice I. French participated in the inception and study design. Melanie S. Reece was the clinical research coordinator who participated in carrying out the study. Marsha Wheeler and Shannon M. Burke were the obstetricians who participated in carrying out the study. John W. Wilson participated in statistical planning and analysis of the study results. Mary A. Harris, James A. McGregor, and Kenneth G. D. Allen wrote the paper.


The authors would like to thank Nadia Marx, MS, RD, for her assistance in validation of the food frequency instrument. The study was approved by the Colorado State Institutional Review Board on November 6, 2001, as Study no. 00-186H and the Colorado Multi-Institutional Review Board on November 15, 2001, as Study no. 01-509. This study was funded by the United States Department of Agriculture (USDA) Grant no. 00-52102-9633; Colorado Agricultural Experiment Station Multistate Project NC-1167; and Martek Biosciences Corporation, Columbia, MD.

The review combined data from 15 randomized controlled trials into a meta-analysis including nearly 1,900 children, many tracked from infancy into mid-childhood. Some studies found small improvements in vision or cognition, but many did not, and when the results were pooled, there was no clear pattern of benefit from DHA added to formula.

Other studies have focused on fish oil or DHA supplementation during pregnancy, when omega-3s can cross the placenta to the developing fetus. The supplements do seem to increase the length of pregnancy by about two days and result in slightly heavier newborns, but this doesn’t translate to a reduction in premature birth, the A.H.R.Q. report said.

Some studies have found that when mothers take fish oil or omega-3 supplements in pregnancy, their children are less likely to have eczema, food allergies or asthma, at least for the first few years of life, but this research is also inconsistent. And as with formula, prenatal DHA supplements don’t seem to make for smarter children. That conclusion was confirmed in a recent randomized controlled trial published in JAMA, which found no effect of prenatal DHA supplementation on children’s I.Q. at age 7.

This type of confusion is common in nutrition research, says Carol Haggans, a registered dietitian and spokeswoman for the National Institutes of Health Office of Dietary Supplements, which publishes advice for consumers about omega-3s and other supplements. In the case of DHA, she said, “There’s a good theoretical basis for it, and then you have the observational studies that show that fish and other types of seafood are beneficial.” But when researchers try to package a nutrient like DHA in a supplement and test it in randomized controlled trials, the same benefits often aren’t observed.

One reason for the conflicting results is that people have different baseline levels of DHA, depending on how much fish they eat, and genetic variations can affect fatty acid metabolism. “If you don’t have a deficient population, then it probably doesn’t matter” if people take a supplement, said Dr. Susan Carlson, professor of nutrition at the University of Kansas Medical Center.

But in the United States, many women don’t seem to be getting enough DHA. Women of childbearing age consume an average of 60 milligrams of DHA per day, but many experts recommend at least 200 milligrams per day during pregnancy and breast-feeding.

That amount of DHA can be obtained by eating eight to 12 ounces of fish per week, as recommended for pregnant or breast-feeding women in the Dietary Guidelines for Americans. Focus on fish varieties high in omega-3s and low in methyl mercury, like salmon, trout, herring and anchovies, the guidelines say.

Generic Name: omega-3 polyunsaturated fatty acids (oh MAY ga 3 POL ee un SAT yoo ray ted FAT ee AS ids)
Brand Name: Divista, Fish Oil, Lovaza, MegaKrill, Nature’s Bounty Red Krill Oil, Prenatal DHA, TheraTears Nutrition, Vascazen, Vayarin, Wellbaby DHA

Medically reviewed by on Apr 25, 2019 – Written by Cerner Multum

  • Overview
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  • Interactions
  • Pregnancy
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What is Prenatal DHA?

There are many brands and forms of omega-3 polyunsaturated fatty acids available. Not all brands are listed on this leaflet.

Prenatal DHA are found in oil from certain types of fish, vegetables, and other plant sources. These fatty acids are not made by the body and must be consumed in the diet. This medicine work by lowering the body’s production of triglycerides. High levels of triglycerides can lead to coronary artery disease, heart disease, and stroke.

Prenatal DHA are used together with diet and exercise to help lower triglyceride levels in the blood.

It is not known if Prenatal DHA will prevent a heart attack or stroke. Talk to your doctor about your risk factors.

Prenatal DHA may also be used for purposes not listed in this medication guide.

Important Information

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not take Prenatal DHA if you are allergic to fish, shellfish, or soybeans.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have other medical conditions, especially:

  • diabetes;

  • liver disease;

  • a heart rhythm disorder;

  • a pancreas disorder;

  • underactive thyroid;

  • if you drink more than 2 alcoholic beverages per day.

It is not known whether Prenatal DHA will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.

It is not known whether omega-3 polyunsaturated fatty acids pass into breast milk or if this could harm a nursing baby. Ask a doctor before using this medicine if you are breast-feeding a baby.

Do not give this medication to anyone under 18 years old.

How should I take Prenatal DHA?

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Swallow the omega-3 polyunsaturated capsule whole. Do not puncture or open the capsule.

This medication works best if you take it with food.

Do not crush, chew, break, or dissolve a delayed-release capsule. Swallow it whole.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

While using Prenatal DHA, you may need frequent blood tests.

Prenatal DHA is only part of a treatment program that may also include diet, exercise, and weight control. Follow your doctor’s instructions very closely.

Store at room temperature away from moisture and heat. Do not freeze.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Prenatal DHA?

Avoid eating foods that are high in fat or cholesterol. This medication will not be as effective in lowering your triglycerides if you do not follow the diet plan recommended by your doctor.

Avoid drinking alcohol. It can increase triglycerides and may make your condition worse.

Prenatal DHA side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using Prenatal DHA and call your doctor at once if you have:

  • fever, chills, body aches, flu symptoms;

  • chest pain; or

  • uneven heartbeats.

Common side effects may include:

  • upset stomach, belching;

  • loss of appetite;

  • diarrhea, constipation;

  • back pain; or

  • dry mouth, altered sense of taste.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Prenatal DHA?

Other drugs may interact with omega-3 polyunsaturated fatty acids, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2018 Cerner Multum, Inc. Version: 6.13.

Medical Disclaimer

More about Prenatal DHA (omega-3 polyunsaturated fatty acids)

  • Side Effects
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  • Drug class: nutraceutical products

Consumer resources

Other brands: Fish Oil, Lovaza, Nature’s Bounty Red Krill Oil, MegaKrill, … +10 more

Professional resources

  • Omega-3-acid Ethyl Esters (AHFS Monograph)
  • … +1 more

Related treatment guides

  • Dietary Supplementation
  • Hypertriglyceridemia

What are the best prenatal vitamins to take?

There are many different prenatal vitamins to choose from, including those available at a pharmacy or online. A doctor may sometimes prescribe prenatal vitamins to women with particular health considerations.

Deciding which prenatal supplements to buy comes down to what they contain. Different women will need different doses of some vitamins and minerals, depending on factors such as diet, age, and activity levels.

Typically, a good prenatal vitamin for most women over 19 years of age should contain:

  • Folic acid: At least 400 micrograms (mcg) before pregnancy, 600 mcg during pregnancy, and 500 mcg when breastfeeding.
  • Vitamin B-12: 2.6–2.8 mcg.
  • Iron: 27 milligrams (mg) in pregnancy and 9–10 mg when breastfeeding.
  • Calcium: 1,000–1,300 mg.
  • Vitamin D: 600 international units (IU).
  • Zinc: 11 mg during pregnancy and 12 mg during breastfeeding.
  • Vitamin A: 750–770 mcg for pregnancy and 1,200–1,300 mcg for breastfeeding.
  • Vitamin B-6: 1.9–2.0 mg.
  • Iodine: 220 mcg during pregnancy and 290 mcg during lactation.


Share on PinterestPrenatal vitamins often contain omega-3 because some pregnant women do not get enough from their diet.

Several other nutrients are also common constituents of prenatal multivitamins, but nutritionists know less about their benefits or how and when to take them.

One example of this is omega-3 fatty acids, compounds that help give structure to cell membranes, especially those in the brain and retina.

According to the National Institutes of Health (NIH), the daily intake need by pregnant women is 1.4 grams (g) and 1.3 g per day for breastfeeding women, compared to 1.1 g per day for other women 14 years of age and older.

But a 2015 systemic review that examined nearly 150 studies looking at the impact of omega-3 supplementation on maternal and fetal health found only a small increase in gestation time and birth weight.

So, while it might not hurt for a prenatal vitamin to include omega-3s, it may not be as necessary as once thought.

Omega-3 fatty acids are commonly in prenatal vitamins because some pregnant women may struggle to get enough in their diet.

Fish and seafood are common sources of omega-3s, but many species contain high levels of mercury that research has associated with birth abnormalities.

Prenatal vitamins with fish or seafood content should only come from species typically low in mercury, such as:

  • catfish
  • salmon
  • pollock
  • shrimp

Seafood species to avoid when pregnant or breastfeeding include:

  • swordfish
  • shark
  • king mackerel
  • marin
  • tilefish
  • orange roughy
  • white tuna

The American College of Obstetricians and Gynecologists list all these species of fish in their advice on nutrition during pregnancy.

If a person has concerns about omega-3 fatty acids from fish or seafood, they can consider plant-based foods and supplements instead.

Some vegetarian and vegan sources of omega-3 fatty acids include chia seeds, seaweed, walnuts, and edamame beans.

Vitamins E and C

Manufacturers typically include vitamins E and C in prenatal multivitamins. As powerful antioxidants, they work together to protect the body from oxidative stress.

Vitamin C also helps make collagen and metabolize folate and iron. The NIH suggest pregnant women consume around 80–85 mg a day and 115–120 mg when breastfeeding.

The NIH also recommend 15–19 mg of vitamin E a day for anyone pregnant or breastfeeding.

Research once suggested taking vitamin E and C together during pregnancy might reduce oxidative stress and its associated complications, such as:

  • preeclampsia
  • pre-labor rupture of membranes (PROM)
  • intrauterine growth restriction

However, the World Health Organization (WHO) currently say that a joint vitamin C and E supplement likely has little impact on women or developing fetuses, and may increase the risk of PROM.

What to know about omega-3 fatty acids

Share on PinterestChia seeds are a good source of omega-3 fatty acid.

Beyond the basic maintenance of cells in a person’s body, initial research has linked omega-3 fatty acids with various other health benefits.

However, a lot of the research that demonstrates these links is in the early stages or relies on experiments on animals.

In general, until scientists conduct further research, it is not clear to what extent omega-3 fatty acids benefit a person beyond the basic maintenance of their body’s cells.

The ODS note that studies have found that people who eat fish, which is a key source of omega-3 fatty acids, typically have a lower risk of various long-term illnesses compared with those who do not eat fish.

However, it is not clear whether this is because of the omega-3s that the fish contain or something else. Furthermore, if it is because of the omega-3s that fish contain, it is not clear if a person taking omega-3 supplements will have the same benefits.

May reduce inflammation

According to an article in the British Journal of Clinical Pharmacology, research has shown DHA and EPA to reduce the process of inflammation, which has links to various cardiovascular illnesses.

However, while these effects were evident in animal studies, clinical trials on humans were less conclusive.

People with rheumatoid arthritis appeared to benefit from taking fish-oil supplements, but there was no clear benefit for people with inflammatory bowel disease or asthma.

May reduce the chance of heart attack

According to the ODS, there is some evidence that taking omega-3 supplements may reduce the risk of a person having a heart attack. However, the ODS note that other studies did not find a link between omega-3 supplements and less chance of a person having cardiovascular issues in general.

A review article in the Journal of Physiology and Biochemistry states that this is a controversial area of research that is still up for debate.

According to the National Centre for Complementary and Integrative Health (NCCIH), researchers have shown omega-3s to help lower a person’s triglyceride levels. Triglycerides are fats, and if a person has an excess of these, they are more at risk of cardiovascular diseases.

However, the NCCIH point out that medications that contain omega-3s among other ingredients have approval by the U.S. Food and Drug Administration (FDA) to treat high triglyceride levels, although the same does not apply to omega-3 supplements.

A 2018 study suggested that taking omega-3 supplements could benefit African Americans. Black participants receiving the supplement saw a 77% reduction in heart attack compared with those taking the placebo.

May help combat obesity

An article in The Journal of Nutritional Biochemistry states that research in humans is yet to show omega-3 supplements to help a person lose weight. They may be able to help a person stop putting weight back on, however, although it is not clear precisely how they may do this.

May contribute to infant health

The NCCIH highlight a study that shows that the children of mothers who took a high-dose fish oil supplement were less likely to develop asthma than the children of mothers who took a placebo. However, the NCCIH also note that other studies contradict this finding.

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