Fertility Nutrition Before Pregnancy: Common Nutrient Gaps (and How to Address Them)

If you’re thinking about trying to conceive, it’s normal to start evaluating your nutrition: what you’re eating, what you may want to add, and whether supplements should be part of your routine. The goal of this article is to help you think clearly about preconception nutrition as one part of overall health planning.

Important note: Fertility is influenced by many overlapping factors (timing, age, underlying medical conditions, anatomy, hormones, genetics, and lifestyle). Nutrition can support general health, but no nutrient, diet pattern, or supplement can guarantee pregnancy. Use this guide as a starting point for a conversation with your healthcare provider.

Overall health and preconception planning

Reproductive health is closely connected to general health. Sleep, stress, alcohol, tobacco and drug use, activity level, and overall dietary patterns can influence hormones and metabolic markers (lab results that give clues about metabolism, such as blood sugar, insulin, or cholesterol levels) that are commonly evaluated in fertility care.

If you’re considering supplements, a practical first step is a baseline visit with your primary care provider, OB‑GYN, urologist, or fertility specialist. When appropriate, your healthcare provider may recommend labs (for example, vitamin D or iron status, and sometimes thyroid testing) to determine whether there’s a true deficiency to correct.

Male fertility matters

Fertility challenges can involve male factors as well as female factors. If pregnancy isn’t happening on the expected timeline, a semen analysis can be a helpful early step, because it provides objective information on sperm count (how many), motility (how well they move), and morphology (shape/structure).

What “fertility supplements” can (and can’t) claim

“Fertility supplements” is a marketing term, not a medical category. In the United States, dietary supplements are regulated differently from medications. Generally:

• Supplements are not reviewed by the FDA for effectiveness before they are sold.
• Products vary in quality and labeling accuracy.
• Supplement labels generally cannot claim to diagnose, treat, cure, or prevent disease.
  
  

That doesn’t mean supplements are inappropriate. It means the safest approach is to treat supplementation as gap-filling support, guided by labs and clinical context, not with a fix-all mindset. 

Nutrients commonly discussed in preconception nutrition

Folate

The neural tube (baby’s brain and spinal cord) closes early in pregnancy (often before someone knows they’re pregnant), so clinical guidelines recommend folate supplementation for those who could become pregnant and for those trying to conceive (1, 2). 

Folate, folic acid, and methylfolate are all forms of vitamin B9. Folate occurs naturally in foods, folic acid is a synthetic form used in supplements and food fortification, and methylfolate (5‑MTHF) is a biologically active form commonly used in supplements. 

Folic acid must be converted in the body to be used. Some people, including those with MTHFR gene variants, may have differences in folate metabolism. Researchers have also studied unmetabolized folic acid (UMFA) in the blood when intake is high from fortified foods and supplements; the clinical significance is still being evaluated. Discuss folate form and dose with your healthcare provider. 

Vitamin D

Vitamin D status varies widely by individual factors (diet, sun exposure, skin tone, geography, body weight). Beyond bone health, vitamin D supports already healthy immune function and helps your body absorb calcium, and for those trying to conceive, it plays a role in reproductive health for both partners.* Because very few foods naturally contain vitamin D, most people get it primarily through fortified foods like milk, cereal, and orange juice, along with fatty fish, egg yolks, and mushrooms exposed to UV light. If you're concerned about vitamin D, lab testing can help guide whether supplementation is appropriate and at what amount (3). 

A 2011 Hollis & Wagner study published in the American Journal of Obstetrics & Gynecology evaluated vitamin D supplementation during pregnancy, including a 4,000 IU/day dose, and reported improved maternal (mother) vitamin D status in the study population. As with any supplement, talk with your healthcare provider about the right quantity for you. 

Iron

Iron needs and tolerance vary significantly by individual. Monitor your iron status with your healthcare practitioner, and if you do need supplemental iron, take it separately from your prenatal or multivitamin to avoid interference with other critical nutrients, and in appropriate doses at their recommendation.

Choline

Choline is a vital nutrient for pregnancy that supports cell growth, brain development, and the healthy formation of the baby's brain and spinal cord, yet approximately 90–95% of pregnant women consume less choline than the recommended daily intake.* Most prenatal supplements skimp on, or don’t contain, this ingredient. Look for around 300 mg to help meaningfully close the gap toward the 450 mg daily target most practitioners recommend. 

Iodine

Iodine is a nutrient that supports already healthy thyroid function and is important during pregnancy and breastfeeding.* Some pregnant people may not get enough iodine from diet alone.* The NIH notes that the Recommended Dietary Allowance (RDA) for iodine is 220 mcg/day during pregnancy (and 290 mcg/day during lactation). Look for a formula with around 250 mcg of iodine per serving. Always consult your healthcare provider to determine the right intake for you, especially if you have thyroid disease or use thyroid medication.

Omega‑3s (EPA/DHA)

Omega-3 fatty acids (EPA and DHA) are essential fats your body can't produce efficiently on its own. They play a meaningful role in reproductive health, pregnancy, and postpartum wellness for both women and men.* Omega‑3 intake can come from food (like oily fish) or supplements (ODS-NIH). If someone doesn't regularly eat omega‑3‑rich foods, supplementation is worth considering for general nutrition support.

One thing worth paying attention to: including EPA and DHA in a prenatal multivitamin, rather than as a standalone fish oil, is worth a second look. Fish oil is highly prone to oxidation (a wear-and-tear process where the fish oil can go bad) and can lose potency (their strength) quickly. Research suggests oxidized oils may have altered biological activity, making them less effective or potentially harmful, and that risk increases when the oil is bundled into a combination multivitamin rather than protected in its own dedicated softgel. Combining the two can also make it harder to dose omega-3s accurately.

Zinc and selenium

Zinc and selenium support already healthy immune, hormone, and thyroid function, and pregnancy tends to increase the need for both, yet many pregnant women fall short of the estimated average requirement for zinc, and selenium levels naturally decline during pregnancy.* When choosing a zinc supplement, look for forms like bisglycinate chelate, which tends to offer strong bioavailability (how easily your body can use it) and gentler on your gut compared to oxide, carbonate, or citrate forms. For selenium, look for L-selenomethionine, the organic form shown to be better absorbed and retained than inorganic forms. As always, talk to your healthcare practitioner about your individual mineral needs, especially if you're taking other supplements containing zinc or selenium. 

CoQ10 (Coenzyme Q10)

CoQ10 is a compound your body naturally produces to fuel cellular energy (help your cells produce the energy your body needs to function), and because eggs and sperm take about 90 days to develop, this preconception window is when nutrient support may matter most for both partners.* Since CoQ10 levels tend to decline with age, many people trying to conceive look to dietary sources like sardines, beef liver, and soybeans or supplementation to help meet their needs during this stage (4, 5).

Calcium

Calcium supports the development of a baby's bones and teeth, along with moms muscle and nerve function, and is one of the more critical minerals to get right during pregnancy.* Yet it's often left out by brands due to its size and because they choose to prioritize iron instead. Calcium and iron compete for absorption, and including both in the same formula undermines the effectiveness of each. Look for at least 200 mg of di-calcium malate in a prenatal to help get closer to your daily requirement, as di-calcium malate is a highly bioavailable, digestive-friendly form of calcium. 

Magnesium

Magnesium may support healthy sleep and mood, and can help ease occasional nausea, yet 48% of Americans fall short of the daily requirement, and 30% of pregnant women taking prenatal supplements still don't meet the requirements.* Over half of pregnant women do not get enough magnesium from diet alone. Form matters as much as quantity with magnesium to ensure absorption and how well you tolerate it. Oxide and carbonate forms can be poorly absorbed and notorious for GI upset, while citrate absorbs better but can have a laxative effect (has a "gets things moving" effect on digestion). Bisglycinate chelate tends to deliver both bioavailability and can be easier on the gut, since a high dose of the wrong form is less impactful than the right form at the right dose. 

B12

B12 plays a key role during pregnancy, supporting the baby's nervous system development.* But with B12, form matters just as much as getting enough of it. Methylcobalamin and adenosylcobalamin are the active forms your cells can readily utilize, so when a brand chooses methylcobalamin, and especially when they pair it with adenosylcobalamin, it signals a formulation built around efficacy, not just a checkbox on a label. 

Safety, Dosage, and Quality: A Few Ground Rules

• Get tested for deficiencies before supplementing where practical. It's more effective (and often cheaper) to correct an actual gap than to guess.
• Choose brands that publish third-party testing results and are transparent about sourcing and manufacturing standards, since products are not vetted for safety or effectiveness before they reach store shelves (6).
• Always check for interactions with any prescription medications, and loop in your pharmacist or provider if you're combining several supplements at once.

The Bottom Line

Nutrient status is one meaningful, modifiable piece of the preconception puzzle, but it's a piece, not the whole picture. The strongest approach combines a nutrient-dense diet, targeted testing, thoughtful supplementation where gaps are identified, and ongoing guidance from a healthcare provider who knows your health history. If something in this guide resonates with your situation, bring it to your next appointment as a conversation starter rather than a self-directed plan.