Nutrient Status and Supplement Use During Pregnancy Following Metabolic Bariatric Surgery : A Multicenter Observational Cohort Study

Introduction: Pregnant women with a history of metabolic bariatric surgery (MBS) are at high risk of developing nutrient deficiencies, leading to greater challenges to reach nutritional requirements. This study compared nutrient status of women using specialized “weight loss surgery” multivitamin supplementation (WLS-MVS) to those using standard supplementation (sMVS) during pregnancy following MBS. Methods: Multicenter observational cohort study including 119 pregnant women at 41.0 (18.5–70.0) months after Roux-en-Y gastric bypass (RYGB, n = 80) or sleeve gastrectomy (SG, n = 39). Routine blood samples were analyzed every trimester (T1, T2, T3), and micronutrient serum levels were compared between WLS-MVS and sMVS users. Results: During pregnancy after RYGB, WLS-MVS users demonstrated higher serum concentrations of hemoglobin (7.4 [7.2, 7.5] vs. 7.0 [6.8, 7.3] mmol/L), ferritin (23.2 [15.0, 35.7] vs. 13.7 [8.4, 22.4] µg/L), and folic acid (31.4 [28.7, 34.2] vs. 25.4 [21.3, 29.4] nmol/L) and lower serum vitamin B6 levels (T1: 90.6 [82.0, 99.8] vs. 132.1 [114.6, 152.4] nmol/L) compared to sMVS users. Iron deficiencies and elevated serum vitamin B6 levels were less prevalent in the WLS-MVS group. During pregnancy after SG, WLS-MVS users showed higher serum vitamin D concentrations (89.7 [77.6, 101.8] vs. 65.4 [53.3, 77.4] nmol/L) and lower serum vitamin B1 concentrations (T2: 137.4 [124.2, 150.6] vs. 161.6 [149.0, 174.1] nmol/L, T3: 133.9 [120.1, 147.7] vs. 154.7 [141.9, 167.5] nmol/L) compared to sMVS users. Conclusion: Low maternal concentrations of micronutrients are highly prevalent during pregnancy after MBS. The use of specialized multivitamin supplementation generally resulted in higher serum levels during pregnancy compared to standard supplementation. Future research is needed to investigate how supplementation strategies can be optimized for this high-risk population. Graphical Abstract: (Figure presented.)