Gestational reactive hypoglycaemia and adverse pregnancy outcomes: a systematic review and meta-analysis.

Background: Reactive hypoglycaemia is a condition where blood glucose drops after a glucose load, and may be associated with adverse pregnancy outcomes. This study aimed to determine the association between gestational reactive hypoglycaemia (GRH) and the risk of adverse pregnancy outcomes including those related to diabetes.

Methods: We performed a systematic review and meta-analysis by searching 4 databases: Medline, Embase, Web of science, and Maternity & infant care database, from inception to 1 December 2023. The outcomes of interest were any reported adverse pregnancy outcomes including large for gestational age (LGA), macrosomia, small for gestational age (SGA), fetal growth restriction (FGR), low birth weight (LBW), caesarean delivery, neonatal intensive care unit (NICU) admission, neonatal hypoglycaemia, polyhydramnios, 5-min APGAR score < 7 and preterm delivery. Risk of bias assessment was performed with Newcastle Ottawa scale. Subgroup analysis was also performed.

Results: From 14,746 records, 42 studies were selected for full-text assessment. Thirty studies reporting on 114,148 participants, including 18,878 women with GRH, fulfilled eligibility criteria. Pregnancies with observed GRH had higher risk of SGA (RR = 1.49, 95%CI = 1.33, 1.68), LBW (RR = 1.35, 95%CI = 1.13, 1.60), FGR (RR = 1.21, 95%CI = 1.05, 1.41), and NICU admission (RR = 1.23, 95%CI = 1.02, 1.49) compared to the euglycaemic group. At subgroup analyses, GRH diagnosed at postload glucose < 3 mmol/l was associated with an increased risk of NICU admission (RR = 3.39, 95%CI = 1.56, 7.34); and GRH limited to post glucose tolerance test (GTT) was associated with increased risk of polyhydramnios (RR = 1.93, 95%CI = 1.17, 3.20) and SGA (RR = 1.90, 95%CI = 1.01, 3.58).

Conclusions: GRH is a condition not routinely diagnosed in pregnancy but associated with adverse fetal-neonatal outcomes as SGA, FGR, and NICU admission. At GTT, GRH is associated with the risk of polyhydramnios. More studies are still necessary to determine the threshold value for diagnosis of GRH and explore associations with other outcomes related to glucose dysmetabolism.