The impact of a vegan diet on pregnancy outcomes

J Perinatol. 2021 May;41(5):1129-1133. doi: 10.1038/s41372-020-00804-x. Epub 2020 Sep 1.


Objective: To determine the effect of a maternal vegan diet on pregnancy outcome.

Study design: This is a prospective observational study. Women with a singleton pregnancy who maintained the same diet prior to, and throughout current pregnancy were enrolled. Stratification was performed according to diet type: vegans, lacto-ovo-vegetarians, fish-eaters, and omnivores.

Results: Overall, 273 women were enrolled, of them, 112 omnivores, 37 fish-eaters, 64 lacto-ovo-vegetarians, and 60 vegans. The vegan diet was significantly associated with an increased risk of small-for-gestational-age newborns compared only to an omnivore diet (RR = 5.9, 95% CI, 1.2-21.8). The incidence of preterm birth was similar in all groups. Vegans had lower birthweight compared to lacto-ovo-vegetarians (3015 ± 420 g vs. 3285 ± 482 g, P = 0.004), and to omnivores (3328 ± 495 g, P < 0.001), but not to fish-eaters. Vegans also had a lower mean gestational weight gain compared only to omnivores (11.6 ± 4.2 kg vs. 14.3 ± 4.6 kg, P = 0.001).

Conclusion: The vegan diet is associated with an increased risk for small-for-gestational-age newborns and lower birthweight.

Publication types

  • Observational Study

MeSH terms

  • Animals
  • Diet
  • Diet, Vegan*
  • Diet, Vegetarian
  • Female
  • Humans
  • Infant, Newborn
  • Pregnancy
  • Pregnancy Outcome / epidemiology
  • Premature Birth*
  • Vegetarians