Bariatric Surgery Associated With Preterm Birth

Abstract

Babies born to women who have undergone bariatric surgery are more likely to be born preterm and small for gestational age, according to a study published online November 12 in BMJ. Researchers from the Karolinska Institutet in Sweden conducted the most extensive study to date on birth outcomes aft er bariatric surgery using data from the Swedish Medical Birth Register and the Patient Register. Th e analysis included more than 2,500 babies born between 1992 and 2009 to mothers who had previously undergone bariatric surgery compared with 12,500 babies born to mothers with no history of bariatric surgery. Th e pregnancies in the two groups were matched so that the mothers’ body mass index (BMI), age, educational background, smoking habits and previous births were comparable in both groups. Infants born to women with a bariatric surgery history were nearly two times more likely to be born before the 37th week of gestation and two times more likely to be small for gestational age compared with infants born to mothers without a history of bariatric surgery. Th e increased risks for preterm birth and small size for gestational age appeared to aff ect only women with an early pregnancy BMI 35 kg/m2. Based on the fi ndings of this large and carefully designed study, the authors contend that pregnancies aft er bariatric surgery should be considered high-risk and monitored closely during the prenatal period.