There are more than 262 scientific texts studying the effects of these diets on pregnancy.¹ : none showed an increase in major malformations in children, and only one showed a slight increased risk of hypostadias (malformation of the penis) in the male child of a vegetarian mother. Five studies have shown a lower birth weight in children of vegetarian mothers, but two studies have shown the opposite results. The duration of pregnancy, on the other hand, remains the same whether you are vegetarian or not.

Nine studies nonetheless shed light on the risks of vitamin B12 and iron deficiency in pregnant vegetarian women. Ultimately, vegan and vegetarian diets can be considered safe, as long as particular attention is paid to the need for vitamins (especially vitamin B12) and trace elements (especially iron). Other research has shown that pregnant vegetarians have much better intakes of magnesium, which can significantly reduce the frequency of calf cramps in the third trimester.².

Piccoli GB, Clari R, Vegan-vegetarian diets in pregnancy: danger or panacea? A systematic narrative review. BJOG. 2015 Apr;122(5):623-33. doi: 10.1111/1471-0528.13280. Epub 2015 Jan 20. C Koebnick, R Leitzmann, & al. Long-term effect of a plant-based diet on magnesium status during pregnancy, European Journal of Clinical Nutrition (2005) 59, 219–225. doi:10.1038/sj.ejcn.1602062 Published online 29 September 2004