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Trying to Conceive: Prenatal Vitamins, Fertility Supplements and What to Stop, by the Evidence

Folic acid is the one prenatal nutrient with top-grade evidence: 400 to 800 mcg a day, started before pregnancy. Choline and iodine are often short in prenatals, and most fertility supplements rest on low-quality trials.

By Kymata Health editorial teamLast verified October 10, 2026

Medical review pending. Written by our editorial team from the studies and documents cited below; a credentialed clinician has not reviewed it yet. Educational only, not medical advice.

Key takeaways

  • The USPSTF recommends 0.4 to 0.8 mg (400 to 800 mcg) of folic acid daily for everyone planning or able to become pregnant, its top A grade [1].
  • In the Medical Research Council trial, folic acid prevented 72% of repeat neural tube defects [2]; the CDC says it is the only form of folate shown to prevent them, including for people with MTHFR variants [3][4].
  • In a 2025 lab analysis of 47 prenatal products, only 12 listed choline and 25 listed iodine, and 20 of those 25 contained more than 20% less iodine than claimed [5].
  • Cochrane rates the evidence that antioxidant supplements such as CoQ10 and myo-inositol raise live births in subfertile women as low to very low quality [6].
  • Semaglutide should be stopped at least 2 months before a planned pregnancy [7], and the CDC says there is no known safe amount of alcohol when trying to conceive [8].

Guides in this hub

  1. Prenatal Vitamins: What the Evidence Says About Folic Acid vs Methylfolate, Choline, DHA and IodineFolic acid, started before pregnancy, is the prenatal ingredient with the strongest evidence. Choline and iodine are the nutrients prenatals most often skimp on, and omega-3s modestly cut early preterm birth.
  2. CoQ10, Myo-Inositol and Other Fertility Supplements: What the Trials Actually ShowCochrane reviews rate the evidence for antioxidant and inositol supplements in women trying to conceive as low to very low quality. CoQ10 looks most promising for women with a poor IVF response, and a large trial of folic acid and zinc for men found no benefit.
  3. Trying to Conceive? Medicines and Supplements to Stop or Review FirstA few things need to stop well before you try: semaglutide at least 2 months ahead, isotretinoin at least 1 month ahead, and high-dose vitamin A. The CDC says alcohol has no known safe amount; ACOG says under 200 mg of caffeine a day is not a major miscarriage risk factor.

Start folic acid before you try

Neural tube defects develop in the first weeks of pregnancy, often before a pregnancy is known, so the CDC advises starting 400 mcg of folic acid a day at least 1 month before conception [3]. The USPSTF puts the range at 400 to 800 mcg with high certainty of substantial benefit [1].

You may hear that people with MTHFR variants need methylfolate instead, but the CDC says they can process folic acid and that folic acid is the only form shown to prevent neural tube defects [4]. Our prenatal vitamin guide compares the ingredients.

What prenatals often miss

Two nutrients are commonly short. Choline: the pregnancy target is 450 mg a day, about 90% to 95% of pregnant women fall short, and prenatals typically contain little if any [9]. Iodine: the American Thyroid Association recommends a 150 mcg supplement when planning, pregnant or breastfeeding [10].

Labels are not always accurate: a 2025 analysis found most products listing iodine contained far less than claimed, and measurable lead in 32 of 47 prenatals, though none exceeded US Pharmacopeia limits [5]. See our choline and iodine monographs.

Fertility supplements

For women, a Cochrane review of 63 trials could not say whether antioxidants, including CoQ10 and myo-inositol, improve live birth, because the evidence was very low quality [6]. For men, the large FAZST trial found folic acid plus zinc did not improve semen quality or live births [11].

Our CoQ10 and myo-inositol guide covers where the evidence is strongest, mainly CoQ10 in women with a poor IVF response.

What to stop first

Wegovy's label says to stop semaglutide at least 2 months before a planned pregnancy [7]. Supplements high in preformed vitamin A are a concern: in one study of 22,748 pregnancies, more than 10,000 IU a day from supplements was linked to 4.8 times the rate of certain birth defects [12]. Our what to stop guide has the full list.

Partners we link to

Paid links: we earn a commission if you buy through these, at no extra cost to you. It never changes what the evidence sections say. Affiliate disclosure.

  • Natural CyclesPaid linkAn app the FDA authorized in 2018 for women 18 and older to monitor their fertility, for preventing a pregnancy or planning one; it reads your temperature data to flag fertile days. It does not protect against STIs.See Natural Cycles

Regulatory and legal notes

  • Prenatal vitamins and fertility supplements are dietary supplements: the FDA does not approve them before they are marketed and does not test them before they are sold [13].
  • A 2025 analysis of 47 US prenatal products found choline and iodine amounts often differed from their labels, and the authors called for stronger federal regulation of supplements [5].
  • In March 2026 Cochrane noted that seven studies in its 2020 review of antioxidants for female subfertility had been retracted and two carried expressions of concern; its editors judged the conclusions unchanged [6].
  • Natural Cycles was authorized by the FDA in 2018 through the De Novo pathway as a software application for women 18 and older to monitor fertility, for preventing or planning a pregnancy [14].

Other names you will see

Listed for completeness. We have no paid relationship with these brands and do not link to them.

  • Needed: Sells prenatal multivitamins and other pregnancy supplements. We have no active partnership and have not vetted its products.
  • FullWell: Sells prenatal and fertility supplements. We have no active partnership and have not vetted its products.

References

  1. [1]Folic Acid Supplementation to Prevent Neural Tube Defects: US Preventive Services Task Force Reaffirmation Recommendation Statement. JAMA, 2023. PMID 37526713
  2. [2]Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet, 1991. PMID 1677062
  3. [3]About Folic Acid (updated September 18, 2026). Centers for Disease Control and Prevention, 2026.
  4. [4]MTHFR Gene Variant and Folic Acid Facts (July 16, 2026). Centers for Disease Control and Prevention, 2026.
  5. [5]Content of selected nutrients and heavy metals in prenatal multivitamins and minerals: an observational study. Am J Clin Nutr, 2025. PMID 40252729
  6. [6]Antioxidants for female subfertility (Cochrane review). Cochrane Database Syst Rev, 2020. PMID 32851663
  7. [7]WEGOVY (semaglutide) injection and tablets: prescribing information. U.S. Food and Drug Administration (Drugs@FDA), 2026.
  8. [8]About Alcohol Use During Pregnancy (reviewed August 14, 2026). Centers for Disease Control and Prevention, 2026.
  9. [9]Choline: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2022.
  10. [10]Iodine: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2024.
  11. [11]Effect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial. JAMA, 2020. PMID 31910279
  12. [12]Teratogenicity of high vitamin A intake. N Engl J Med, 1995. PMID 7477116
  13. [13]Questions and Answers on Dietary Supplements. U.S. Food and Drug Administration, 2026.
  14. [14]De Novo classification request DEN170052: Natural Cycles (decision summary). U.S. Food and Drug Administration, 2018.

Dietary supplements are not intended to diagnose, treat, cure or prevent any disease, and these statements have not been evaluated by the FDA. Prescription options need a licensed clinician. Talk to your clinician or pharmacist before starting anything new, especially if you take prescription medicines, are pregnant or breastfeeding.

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