Reactive hypoglycaemia at glucose tolerance test—another presentation of gestational diabetes: a multicentre retrospective study

Objective: To assess obstetric outcomes in pregnant women with ‘reactive hypoglycaemia’ (RH) during an oral glucose tolerance test (OGTT), defined as a 2‐h blood glucose level lower than the fasting value.

Design: Retrospective observational study.

Setting: Two tertiary maternity units in the United Kingdom.

Population: A total of 1498 women with singleton pregnancies attending for an OGTT between April 2019 and July 2020.

Methods: Maternal and neonatal outcomes were compared between three groups: gestational diabetes, reactive hypoglycaemia and normal OGTT. Both logistic and linear regression models were used, which adjusted for maternal age at booking, ethnicity, parity and BMI.

Main Outcome Measures: Abdominal circumference > 95th centile, polyhydramnios, gestational age at delivery, preterm birth, birthweight, neonatal hypoglycaemia, admission to neonatal unit, perinatal mortality.

Results: Of the 1498 women, 26.7% (n = 400) had reactive hypoglycaemia, 27.8% (n = 417) GDM and 45.4% (n = 681) normal GTT. The reactive hypoglycaemia group were twice as likely to develop polyhydramnios compared with both the GDM (OR 2.77, 95% CI 1.40–5.50) and control groups (OR 2.47, 95% CI 1.31–4.65). Relative to those with GDM, women with reactive hypoglycaemia had a similar mean birthweight (mean difference 59.4 g, p = 0.06) but were less likely to experience neonatal hypoglycaemia (OR 0.30, 95% CI 0.001–0.15) or preterm birth (OR 0.33, 95% CI 0.18–0.60). No differences were found in maternal hypertensive disorders, abdominal circumference > 95th centile, shoulder dystocia, Apgar < 7, cord pH, admission to neonatal unit or perinatal mortality.

Conclusion: Women with reactive hypoglycaemia in this sample were at risk of adverse outcomes frequently associated with diabetes, including polyhydramnios.