Many pregnant women wonder whether they should avoid certain "healthy" foods during pregnancy due to potential risk to the fetus. Though some researchers have suggested soy milk might harm a developing baby because of the high levels of estrogen-like chemicals in the soy, recent research suggests that pregnant women can drink soy milk without trouble. Further, soy milk contains valuable nutrients that make it healthy for you during pregnancy.
During pregnancy, you need to eat foods that have high nutritional content relative to their caloric content to ensure you're providing your developing baby with plenty of vitamins and minerals. While you need more calories during pregnancy than you do when you're not pregnant, your caloric needs don't increase tremendously. As such, Dr. Miriam Stoppard recommends in "Conception, Pregnancy and Birth" that you avoid foods with added sugars and fats, and eat naturally lean, wholesome foods. Soy milk falls into this category.
Soy is a source of lean protein, meaning that it's more heart-healthy as a protein source than many higher-fat animal sources. Additionally, most soy milks are calcium-fortified, meaning they contain added calcium. This important mineral helps your baby build strong bones. Soy also contains small amounts of essential omega-3 fatty acids. The Silk soy milk website notes that they add extra omega-3 fatty acids to certain of their products, providing you with even more of these valuable, healthy fats.
IIn recent years, there's been some question as to whether soy milk might harm a developing baby because it contains phytoestrogens, which are chemicals very similar in shape to the human hormone estrogen. A 1999 study in the "American Journal of Obstetrics and Gynecology" suggests that consuming very large quantities of soy while pregnant might affect fetal development and cancer risk. However, this study had a sample size of only seven women.
What Research Shows
Most of the research on soy suggests that it doesn't do pregnant women -- or their developing babies -- any harm. A 2002 study in "The Journal of Nutrition" looked at infants fed soy formula. Infants consuming soy formula consume more soy per unit body weight than any other group in the U.S., meaning if soy has a detrimental effect, it will be most apparent in the infant group. The study showed no ill effects of soy.