Assessment of glucose regulation in pregnancy after gastric bypass surgery

Abstract

Aims/hypothesis Roux-en-Y gastric bypass (RYGB) surgery is characterised by glycaemic variability. Prospective studies of glucose metabolism in pregnancy after RYGB are not available, therefore this study aimed to evaluate physiological alterations in glucose metabolism in pregnancy following RYGB. Methods Sixty-three pregnant women (25 who underwent RYGB, 19 non-operated obese control women and 19 normal weight control women) were included. Frequently sampled 3 h OGTTs and 1 h IVGTTs were performed between 24 and 28 weeks of gestation and, in a subgroup, were repeated at 3-6 months after delivery. Results We observed major alterations in glucose kinetics during the OGTT, including an early increase in plasma glucose followed by hypoglycaemia in 90% of women who had previously undergone RYGB. The higher degree of glycaemic variability in this group was accompanied by increased insulin, C-peptide and glucagon concentrations after oral glucose load, whereas no differences in insulin response were observed after parenteral glucose administration (RYGB vs normal weight). IVGTT data suggested improved insulin sensitivity (mean difference 0.226 × 100.104, 0.348]; p < 0.001) and disposition index in pregnancies after RYGB when compared with obese control women. However, subtle alterations in insulin action and beta cell function were still observed when comparing women who had undergone RYGB with the normal-weight control group. Moreover, we observed that fetal growth was associated with maternal glucose nadir levels and insulin secretion in offspring of those who had previously undergone RYGB. Conclusions/interpretation Pregnancies after RYGB are affected by altered postprandial glucose, insulin and C-peptide dynamics. Insulin sensitivity is improved by RYGB, although subtle alterations in beta cell function are observed. Longitudinal studies are needed to assess potential consequences for fetal development and pregnancy outcomes.

Trajectories of Fetal Adipose Tissue Thickness in Pregnancies After Gastric Bypass Surgery

“…Moreover, increased fetal subcutaneous fat tissue is known to be a consequence of maternal diabetes and was shown to be more closely related with poor glycemic control than neonatal birth weight [16], suggesting that alterations in maternal glucose metabolism after bariatric surgery contribute to our observation of altered fetal subcutaneous fat trajectories. This is also supported by another recent study on women after GB indicating that birthweight percentiles are related to maternal hyperinsulinemia and glucose nadir levels during a 3-h 75 g OGTT [19]. However, although postprandial hypoglycemia during a routinely performed 2 h OGTT was frequently observed in the present study, we failed to identify a clear association with reduced FSCTT.…”

Intrauterine Fetal Growth Delay During Late Pregnancy After Maternal Gastric Bypass Surgery

“…Moreover, continuous glucose monitoring during pregnancy revealed that RYGB patients spend over 13 % of their time with blood glucose levels below 60 mg/dl [20]. A possible relation between fetal growth and glycemic dysregulation in mothers after GB surgery was also underlined by our previous study where glucose nadir and insulin response during an OGTT were associated with lower birth weight percentiles as well [17]. The two most common types of bariatric surgery, gastric bypass and gastric banding, seem to affect pregnancy outcomes differently.…”

“…3). Bariatric surgery was shown to severely affect glucose metabolism in pregnant and non-pregnant patients [6,17]. Within the last decade, the focus was set on investigating maternal hyperglycemia and its impact on fetal growth due to the rising prevalence of obesity-linked gestational diabetes.…”

Management of Pregnant Women after Bariatric Surgery

“…Depending on the type of bariatric surgery (e.g., RYGB), fast glucose absorption during an OGTT might lead to severe postabsortive hypoglycaemia [ 7 ]. Recent evidence demonstrates difficulties in the interpretation of OGTT results as plasma glucose concentrations after oral glucose load are altered following gastric bypass and characterized by rapidly changing glucose levels as well as high risk for reactive hypoglycaemic events following glucose load [ 34 – 37 ]. This might lead to misinterpretation of postprandial glucose levels as one-hour levels misleadingly appear too high, and two-hour levels appear too low, and thus, diagnostic alternatives to define impaired glucose tolerance in pregnancies affected by metabolic surgery need to be found.…”

“…Due to changes in glucose absorption after bariatric procedures, rapid postprandial plasma glucose increases followed by rapid decreases and risk for dumping syndrome occur in many patients. In pregnant women after RYGB, postprandial hypoglycaemia was reported in nearly 55% up to 90% of women after a 75 g OGTT between 24 and 28 weeks of gestation [ 34 , 37 ]. Furthermore, higher incidence of SGA offspring and associations of postprandial glucose nadir with fetal growth were reported [ 34 , 37 ].…”