Walk into any pharmacy and the supplement shelves are overwhelming. "Fertility support." "Conception blend." "Prenatal plus." The marketing is sophisticated; the underlying evidence varies enormously. Here's a frank breakdown of what's actually worth taking — graded by the quality of evidence behind it.
The most important pre-conception supplement. Folate is required for neural tube closure at days 22–28 post-conception — before most women know they are pregnant. Supplementation reduces neural tube defect (NTD) risk by ~70%. Women with prior NTD-affected pregnancies, diabetes, or on anti-epileptics should take 5mg daily (prescription). Note: some women carry MTHFR polymorphisms affecting folate metabolism — if this is a concern, methylfolate (active form) may be preferable.
Vitamin D deficiency is remarkably common in Singapore despite year-round sunshine — largely due to indoor lifestyles and sun avoidance. Vitamin D receptors are expressed in ovarian follicles and endometrial cells. Deficiency is associated with reduced IVF success rates, PCOS severity, and adverse pregnancy outcomes. Aim for serum 25-OH vitamin D ≥50 nmol/L pre-conception.
Iodine is required for thyroid hormone synthesis, which is critical for fetal brain development. Singapore's iodine intake may be suboptimal — included in most prenatal multivitamins but worth checking the label. WHO-recommended supplementation for women planning pregnancy.
Routine iron supplementation in iron-replete women is not recommended and may cause GI side effects. However, iron-deficiency anaemia impairs ovulation and is common in women of reproductive age — particularly in vegetarians/vegans. Check FBC first, then treat if indicated.
DHA is incorporated into oocyte and sperm membranes and is critical for fetal brain and retinal development in the third trimester. Evidence supports DHA supplementation in women with low fish intake. Most prenatal vitamins do not include adequate omega-3 — check the label. Algae-based DHA is suitable for vegetarians.
CoQ10 is a mitochondrial antioxidant involved in oocyte energy metabolism. Mitochondrial function declines with maternal age, contributing to reduced oocyte quality. Observational and small RCT data suggest potential benefit in diminished ovarian reserve and older reproductive-age women. Not standard of care but reasonable to consider.
Reasonably well-evidenced specifically in women with PCOS — improves insulin sensitivity, reduces androgen levels, and may restore ovulation. Not indicated for women without PCOS. Some evidence for improving egg quality in IVF cycles.
Most commercially marketed "fertility supplements" contain combinations of antioxidants, herbs, and vitamins at doses that are too low to be individually therapeutic. The clinical evidence for these proprietary blends is largely industry-funded and methodologically weak. A good prenatal multivitamin covering folate, vitamin D, iodine, and iron is typically better value.
💡 Practical recommendation: Start with a quality prenatal multivitamin containing methylfolate (400–800 mcg), vitamin D (1,000 IU), iodine, and iron. Add DHA if fish intake is low. Add CoQ10 if you're over 35 or have diminished ovarian reserve. Keep it simple.
References
USPSTF Recommendation: Folic Acid Supplementation to Prevent Neural Tube Defects (2023)
Lerchbaum E & Obermayer-Pietsch B. Vitamin D and fertility: a systematic review. Eur J Endocrinol. 2012
Ben-Meir A et al. Coenzyme Q10 restores oocyte mitochondrial function and fertility during reproductive aging. Aging Cell. 2015
Unfer V et al. Myo-inositol effects in women with PCOS: a meta-analysis. Gynecol Endocrinol. 2016
WHO Global Iodine Deficiency Disorders Guidelines (2022)