New research in the American Journal of Clinical Nutrition suggests that a healthy diet around the time of conception through the second trimester may reduce the risk of pregnancy-related complications, including gestational diabetes (GDM), hypertension, preeclampsia, and preterm delivery.
Healthy diets are known to reduce risks of chronic diseases, but how much is known about their impact on common pregnancy complications? To answer this question, Cuilin Zhang, MD, Ph.D. and colleagues at the National Institutes of Health’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) conducted a study. They used dietary data, collected multiple times during pregnancy, from the NICHD Fetal Growth Study.
Approximately 1,900 women responded to a dietary questionnaire at 8 to 13 weeks of pregnancy, which included an estimation of their diets in the previous 3 months. At 16 to 22 weeks and 24 to 29 weeks, the same group identified their dietary intake in the previous 24 hours. Researchers used 3 measures of healthy eating to score the answers: the Alternate Healthy Eating Index (AHEI), Alternate Mediterranean Diet (AMED), and the Dietary Approaches to Stop Hypertension (DASH) diet. In all 3 measures, red and processed meat were limited, and consumption of fruits, vegetables, whole grains, nuts and legumes was encouraged.
Women with high AHEI scores at 16 to 22 weeks had a 32% lower risk for GDM than women with a low AHEI score. Women with high DASH scores at 8 to 12 weeks and 16 to 22 weeks had a 19% lower risk for pregnancy-related high blood pressure disorders. At 24 to 29 weeks, high AMED and DASH scores were associated with a 50% lower risk for preterm birth than women with low scores.
Researchers found that high AHEI scores were related to low GDM risk at 16 to 22 weeks [adjusted RR (95% CI), highest (Q4) vs. lowest quartile (Q1): 0.32 (0.16, 0.66), P-trend = .002]; DASH scores and gestational hypertension risk at 8 to 13 weeks [adjusted RR (95% CI), Q4 vs. Q1: 0.45 (0.17, 1.17), P-trend = .04] and at 16 to 22 weeks [adjusted RR (95% CI), Q4 vs. Q1: 0.19 (0.05, 0.65), P-trend= .01].
At 24 to 29 weeks, higher AHEI scores were linked to lower preeclampsia risk [adjusted RR (95% CI), Q4 vs. Q1: 0.31 (0.11, 0.87), P-trend = .03]. Preterm delivery risk decreased as AMED scores increased at 8 to 13 weeks [adjusted RR (95% CI), Q4 vs. Q1: 0.50 (0.25, 1.01), P-trend = .03]. It also decreased with increasing DASH scores at 24 to 29 weeks [adjusted RR (95% CI), Q4 vs. Q1: 0.50, (0.26, 0.96), P-trend = .03].
“Our study presents the first evidence that the 3 healthy dietary pattern scores were generally inversely related to gestational hypertension and preeclampsia risks across visits, with significant associations for DASH during periconception through mid-pregnancy, and AHEI at 24 to 29 weeks, respectively,” the authors wrote.
This research suggests that, by following any of the 3 diets from the time of conception to the second trimester, the risk of gestational diabetes, hypertension, preeclampsia, and preterm delivery may decline.
Li M, Grewal J, Hinkle SN, et al. Healthy dietary patterns and common pregnancy complications: a prospective and longitudinal study. Am J Clin Nutr. June 2021. doi:10.1093/ajcn/nqab145