March 15, 2026

Fertility Q&A: Prenatal Vitamins, IVF Labs, Pregnancy Spacing & More

12 minutes

Dr. Natalie Crawford, board-certified OB-GYN and REI, answers your fertility questions.

1. When taking a prenatal vitamin, how should we interpret the amount of choline listed on the label? If a prenatal lists 300 mg of choline, is that the full amount counted toward the recommended intake, or does it refer to elemental choline?

2. Is sucralose safe to consume while trying to conceive or during pregnancy, or should it be avoided?

3. I’ve heard that high levels of biotin can interfere with certain blood tests. If a prenatal contains 1000 mcg of biotin and someone is going through IVF with frequent lab work, is that amount considered too high? Should they consider switching prenatals?

4. I’m 38, recently diagnosed with PCOS, and have experienced eight miscarriages. I’ve also been told I have a weak and shortened cervix and have already had a vaginal cerclage twice without success. Are there any additional options or treatments that could be considered?

5. I’m 38 and recently had a baby conceived naturally, though it took some time to get pregnant. I know the general recommendation is to wait about 18 months before trying to conceive again, but I’m worried that waiting too long could make it harder to get pregnant because of my age. How should someone balance recommended spacing between pregnancies with age-related fertility considerations?

Pre-order Dr. Crawford's debut book, The Fertility Formula, now! https://www.nataliecrawfordmd.com/book

Want your questions answered on the next episode? ⁠Ask them here! https://www.nataliecrawfordmd.com/qa-submissions

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