Case study A 25-year-old woman with morbid obesity, acanthosis nigricans, polycystic ovarian syndrome, oligomenorrhoea and primary infertility and childhood-onset absence seizures underwent Roux-en-Y gastric bypass (RYGB) surgery. A year later, her weight had reduced from 125 to 78 kg and body mass index (BMI) from 47∙6 to 29∙7 kg/m2. This was accompanied by a remarkable resolution of acanthosis nigricans and restoration of normal menstruation, and she soon became pregnant spontaneously. She started experiencing symptomatic hypoglycemic episodes 1 to 3 h after food early in pregnancy. Fingerprick capillary blood glucose (cBG) monitoring and continuous glucose monitoring (CGM; MiniMed Paradigm 522, Medtronic®) confirmed non-fasting, postprandial hypoglycemia, with glucose levels of less than 2.2 mmol/L. Fasting plasma glucose was 4∙2 mmol/L, serum insulin 51 IU/L and C-peptide 418 pmol/L. Urine tested negative for sulphonylureas. Serum cortisol, thyroid hormones and vitamin and micronutrient levels were satisfactory. Despite dietary management with a low glycemic index (GI) diet postprandial hypoglycemia increased in severity and frequency, raising concerns of the risk of maternal neuroglycopenia and foetal hypoglycemia. After careful consideration of further options of management, she was commenced on acarbose in incremental doses up to 100 mg three times daily in the second trimester. Acarbose was well tolerated with significant reduction in hypoglycemia frequency and severity on cBG and CGM. She proceeded to term and delivered a healthy girl who is developing normally. Magnetic resonance imaging of the pancreas postdelivery revealed no abnormalities, and there was no further significant hypoglycemia on cBG and CGM. She went on to have a second pregnancy 2 years later. She again experienced hypoglycemic episodes, typically associated with consumption of high GI foods but not with low GI foods. The hypoglycemia was not as severe or as frequent as in the first pregnancy and was managed by low GI diet without resorting to acarbose. She proceeded to term and delivered a healthy boy who is also developing normally.