Introduction
Gestational diabetes mellitus (GDM) is a common pregnancy complication, with prevalence estimates being 1–36%, depending on the population studied and diagnostic criteria employed 1-5. GDM is defined as preconceptionally unconfirmed glucose intolerance identified in the second or third trimester of pregnancy6. Adverse perinatal outcomes associated with uncontrolled diabetes in pregnancy include spontaneous abortion, foetal anomalies, preeclampsia, stillbirth, macrosomia, neonatal hypoglycaemia, and neonatal hyperbilirubinemia, among others7. Women with a history of GDM are at a higher risk of type 2 diabetes than their counterparts8, 9.
Low birth weight (LBW) and preterm birth are the leading causes of neonatal death and childhood-onset morbidity10-12. Approximately 10–15% of infants are born small or premature worldwide 11, 13. Children who survive are at a higher risk of diseases, such as type 1 and 2 diabetes mellitus, hypertension, obesity, and kidney disease, in adulthood 14-16. The exact mechanism underlying these risks remains unclear; the Barker hypothesis proposes that pregnancy may activate biological vulnerability in utero17-19.
A narrative review reported in 2007 that women born with LBW are at risk of GDM 20, but included a small number of studies, and additional research has been published subsequently21-26. There is no quantitative summary of the relevant evidence to date. We performed the first systematic review and meta-analysis of observational studies examining the association between preterm birth, with LBW, or with SGA status and the future risk of GDM.