Myth-buster
A meta-analysis of 17 trials found vitamin C during pregnancy raised birth weight by 52 grams — a difference too small to rule out chance.
This is one of the first meta-analyses on this pairing, so the null result neither proves nor disproves a tiny benefit, but it adds weight to the growing evidence that popping extra vitamin C during pregnancy doesn't meaningfully improve key outcomes like birth weight, preterm birth, or NICU stays.
Researchers pooled data from 567 pregnant women who took vitamin C (alone or with vitamin E) and found their babies were born about 52 grams heavier on average — but the statistical margin of error was wide (from 20 grams lighter to 124 grams heavier), so the result is not reliable. The same analysis also found no significant effect on preterm birth, neonatal death, NICU admission, or gestational age, suggesting that if vitamin C does anything for these outcomes, the effect is too small to detect in this dataset.
Where this fits in the evidence
This is among the first studies we've indexed on Vitamin C for Increased Birth Weight — treat it as an early signal until more research accumulates.
The study
- Meta-Analysis
- n = 567
- 2025
- Revista brasileira de ginecologia e obstetricia : revista da Federacao Brasileira das Sociedades de Ginecologia e Obstetricia
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.