The impact of a vegan diet on pregnancy outcomes.

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.

Does vegan diet influence umbilical cord vitamin B12, folate, and ferritin levels?

PURPOSE: To determine the influence of maternal diets on maternal and umbilical cord blood levels of vitamin B12, folic acid, ferritin, and hemoglobin. METHODS: A prospective observational study on women who maintained the same diet for at least 3 months prior to, and throughout current pregnancy. Women were divided according to their diet. Diet questionnaires were filled in during the 3rd trimester. Blood samples for complete blood counts and levels of ferritin, vitamin B12, folate, and albumin were taken from the women prior to delivery and from the umbilical cord immediately after delivery. RESULTS: The 273 enrolled women included 112 omnivores, 37 pescatarians, 64 vegetarians, and 60 vegans. There were no significant differences in the maternal B12 levels between the study groups (P = 0.426). Vegans had lower maternal ferritin levels compared to pescatarians (27 ± 17 vs 60 ± 74 ng/ml, respectively, P = 0.034), but not compared to vegetarians (P = 0.597), or omnivores (P = 1.000). There were no significant differences in the umbilical cord B12, folate, ferritin, and hemoglobin levels between the study groups. A sub-analysis that compared women who consumed multivitamins, B12 and iron supplements during pregnancy to women who did not, revealed differences in the levels of umbilical-cord B12 (1002 ± 608 vs 442 ± 151 pg/ml, respectively, P = 0.000) and maternal blood B12 (388 ± 209 vs 219 ± 95 pg/ml, respectively, P = 0.030) only among vegans, but not among omnivores. CONCLUSION: Vegan diet does not change the umbilical cord levels of B12, folic acid, ferritin, and hemoglobin. Vegans who do not take any vitamin supplementation are at greater risk for B12 deficiency than omnivores.