Strict vegetarian diets are gaining popularity, but concerns remain about their safety during pregnancy. A recent study found that pregnant women following strict vegetarian diets are 2.7 times more likely to have a small-for-gestational-age infant, with their newborns weighing an average of 240 grams (about half a pound) less at birth.

Researchers conducted a systematic review and meta-analysis of eight studies involving more than 72,000 participants. They examined key pregnancy outcomes, including birth weight, the risk of small-for-gestational-age infants, gestational diabetes, hypertensive disorders, and gestational weight gain.

They found that pregnant women adhering to strict vegetarian diets were 2.7 times more likely to have a small-for-gestational-age infant compared to those consuming animal products. Their infants also weighed, on average, 240 grams (approximately half a pound) less at birth. While strict vegetarian diets were linked to lower gestational weight gain, they did not affect the risk of gestational diabetes or hypertensive disorders.

These findings suggest that without careful planning, strict vegetarian diets during pregnancy increase the risk of inadequate fetal growth. Ensuring sufficient intake of essential nutrients—such as vitamin B12, iron, omega-3 fatty acids, and iodine—through supplementation or fortified foods could help reduce this risk. Learn more about how to have a healthy pregnancy in Aliquot #100: Optimizing for a Healthy Pregnancy & Early Childhood.