Pregnant women with previous bariatric surgery are at high risk of preeclampsia: A multicenter case series and narrative literature review

Aim: This study aimed to clarify outcomes of pregnancies in women with previous bariatric surgery (BS). Methods: A national questionnaire was conducted targeting all 408 perinatal institutions in Japan. Reponses were obtained from 229 institutions, of which four reported a total of five singleton pregnancies and subsequent deliveries in women with previous BS in 2018. Outcomes of these women (BS group) were investigated. Case presentations: One woman (20.0%) delivered without preeclampsia prior to undergoing BS. Among the five women, median maternal age was 36 years, and median interval between previous BS and conception was 28 months. Mean maternal body mass index decreased by 10.5 between BS and conception and increased by 4.57 between conception and delivery. Three women (60.0%) developed preeclampsia (hypertension and proteinuria), two women had chronic hypertension at conception that developed into superimposed preeclampsia, and one woman had new-onset preeclampsia. Three women (60.0%) had type 2 diabetes mellitus (including overt diabetes in pregnancy), and none had new-onset gestational diabetes mellitus. One woman had a preterm delivery at 32 gestational weeks via cesarean section due to abruptio placentae caused by preeclampsia. All five women gave birth to live appropriate-for-gestational age infants with no abnormalities. Conclusion: The incidence of preeclampsia is high among pregnant women with previous BS who have diabetes mellitus at conception.