A healthy diet around the time of conception through the second trimester may reduce the risk of several common pregnancy complications, suggests a study by researchers at the National Institutes of Health. Expectant women in the study who scored high on any of three measures of healthy eating had lower risks for gestational diabetes, pregnancy-related blood pressure disorders and preterm birth. The study was conducted by Cuilin Zhang, MD, PhD, and colleagues at NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). It appears in the American Journal of Clinical Nutrition.

The researchers analyzed dietary data collected multiple times during pregnancy from the NICHD Fetal Growth Study. Nearly 1,900 women responded to questionnaires on their diets at eight to 13 weeks of pregnancy and were asked to estimate what they ate in the previous three months. At 16 to 22 weeks and 24 to 29 weeks, the women identified what they ate in the previous 24 hours. Their responses were scored according to three measures of healthy eating: the Alternate Healthy Eating Index (AHEI), Alternate Mediterranean Diet (AMED), and Dietary Approaches to Stop Hypertension (DASH) diet. All three measures emphasize consumption of fruits, vegetables, whole grain, nuts and legumes while limiting red and processed meat.

Overall, the researchers found that following any of the diets around the time of conception through the second trimester was associated with a lower risk of gestational diabetes, hypertension, preeclampsia and preterm delivery. For example, women with a high AHEI score at 16 to 22 weeks had a 32% lower risk for gestational diabetes than women with a low AHEI score. Women with a high DASH score at eight to 12 weeks and 16 to 22 weeks had a 19% lower risk for pregnancy-related high blood pressure disorders. A high AMED score at 24 to 29 weeks or a high DASH score at 24 to 29 weeks was associated with a 50% lower risk for preterm birth.