Higher maternal body mass index before or during early pregnancy is associated with an increased risk of fetal death, stillbirth and infant death, and women who are severely obese have the greatest risk of these outcomes from their pregnancy, according to a study.
Approximately 2.7 million stillbirths occurred worldwide in 2008, according to background information in the study, which was published in the April 16 issue of the Journal of the American Medical Association. In addition, an estimated 3.6 million neonatal deaths occur each year.
Several studies have suggested that greater maternal BMI before or during early pregnancy is associated with an increased risk of fetal death, stillbirth, perinatal death, neonatal death and infant death, although not all studies have found a significant association. The optimal prepregnancy BMI to prevent fetal and infant death has not been established.
Dagfinn Aune, MS, of Imperial College London, and colleagues conducted a review and meta-analysis to examine the association between maternal BMI (before or in early pregnancy) and risk of fetal death, stillbirth and infant death. After a search of the medical literature, the researchers identified 38 studies that met criteria for inclusion in the meta-analysis, which included more than 10,147 fetal deaths, more than 16,274 stillbirths, more than 4,311 perinatal deaths, 11,294 neonatal deaths and 4,983 infant deaths.
The researchers found even modest increases in maternal BMI were associated with increased risk of fetal death, stillbirth, neonatal death, perinatal death and infant death. The greatest risk was observed in the category of severely obese women, with a BMI of 40 linked to an approximately two- to threefold increase in risk of these outcomes compared with a BMI of 20.
The authors suggest several biological mechanisms could explain the association found in this study, including that being overweight or obese has been associated with increased risk of preeclampsia, gestational diabetes, type 2 diabetes, gestational hypertension and congenital anomalies. These conditions have been strongly associated with risk of fetal and infant death.
Weight management guidelines for women who plan pregnancies should take these findings into consideration to reduce the burden of fetal deaths, stillbirths and infant deaths, the authors wrote.
Study abstract: http://jama.jamanetwork.com/article.aspx?articleid=1860462