What is the effect of antioxidant vitamins C & E on preeclampsia and preterm birth according to reviews?

• A. Slight decrease in preeclampsia and a corresponding decrease in preterm birth
• B. No effect on preeclampsia or preterm birth
• C. Increase in preeclampsia risk
• D. Slight decrease in preeclampsia but no reduction in preterm birth

Answer: (D)

Antioxidant vitamins C and E were studied because the idea was that reducing oxidative stress in pregnancy might lower the risk of preeclampsia. When researchers pool data from multiple randomized trials, the overall message of reviews is that these supplements do not meaningfully decrease preeclampsia, and they do not reliably reduce preterm birth either. Some analyses note a small, inconsistent signal suggesting a slight reduction in preeclampsia in certain subgroups or under specific conditions, but this finding is not robust across studies and does not translate into fewer preterm births. Variability in trial design—such as when supplementation started, the doses used, and adherence—helps explain why results are not consistent. Given the totality of evidence, the most supported takeaway is that there may be a minor, not dependable reduction in preeclampsia, but no reduction in preterm birth.