Insufficient Implementation of Recommendations in Pregnancies after Bariatric Surgery: Results from a Nationwide Real-World Study in Germany (PABS Study).

Introduction Bariatric metabolic surgery (MBS) is increasingly performed in women of reproductive age. Although MBS reduces obesity-related pregnancy complications, altered metabolism and nutritional deficiencies may adversely affect maternal and neonatal outcomes. This study evaluated (1) adherence to current guideline recommendations and (2) pregnancy outcomes in women after MBS in Germany. Materials and Methods In this multicenter cohort study, 410 pregnancies after MBS were collected between 2023 - 2025; 380 cases with complete data on BMI, MBS type, and birth weight were finally analyzed. Maternal characteristics, surgical details, preconceptional and prenatal care, and perinatal outcomes were descriptively assessed and compared with national reference data. Results Preconceptional BMI was 30.1 kg/m 2 , 52% of the women were obese. Most common procedures were Roux-en-Y gastric bypass (RYGB; 58%) and sleeve gastrectomy (38%). Overall, 16% of the women conceived < 1 year after MBS, 27% after 1 - 2 years, and 57% after > 2 years. Before conception, 35% of the women neither received supplementation nor assessment for deficiencies (52%); similar rates were observed during pregnancy. Anemia occurred in 40%, particularly after RYGB. Oral glucose tolerance testing for gestational diabetes screening was used in 33% despite recommendations against it after MBS. Gestational diabetes was diagnosed in 23%. Rates of small and large for gestational age newborns were 20% and 6%, respectively; preterm birth occurred in 10% and C-section in 46%. Conclusions High rates of anemia and SGA highlight the need for specialized high-risk pregnancy care after MBS. Several guideline recommendations regarding surgery-to-conception interval, supplementation, and GDM screening were not consistently followed.