Maternal impacts and perinatal outcomes after three types of bariatric surgery at a single institution

Purpose Bariatric surgery is widely known to improve pregnancy outcomes and to increase the risk of having small for gestational age neonates. However, the specific causes of neonatal growth restriction are still unclear. This study aimed to investigate the impacts of bariatric surgery on pregnancy and perinatal status at a single institution. Methods 24 women delivered singleton births among the 193 reproductive-aged women who underwent bariatric surgery. We classified the surgery into three types: laparoscopic adjustable gastric banding (LAGB; n = 6), laparoscopic sleeve gastrectomy (LSG; n = 5), and malabsorptive surgery (MS; n = 13), and investigated the pregnancy complications and perinatal impacts. Results The median maternal weight gain after LAGB was 12.5 kg (LSG 6.9 kg, MS 9.0 kg). Gestational hypertension was observed in half of the women who underwent LAGB, but in none of those who underwent MS. No significant difference in neonatal birth weight was observed between the LAGB (median 3272 g) and LSG (median 3005 g) groups. The maternal impact after MS was a remarkable decrease in hemoglobin during prepregnancy (median 1.9 g/dl). About 69% of women developed gestational anemia after MS, and their neonatal birth weight was the lowest (median 2660 g). However, the birth weight of neonates delivered by mothers without anemia after undergoing MS was similar to that of those delivered by mothers after undergoing other types of bariatric surgery (median 3037 g). Conclusions Maternal anemia after MS may lead to low neonatal birth weight, which could be attributed to the large-scale reduction in maternal micronutrient levels.