Background
Presence of hyperglycemia in pregnancy is called gestational diabetes mellitus (GDM) and typically diagnosed between 24 and 28 weeks of gestation (conventional GDM; cGDM). Increasingly, such hyperglycaemia is detected early in pregnancy termed as ‘early pregnancy GDM (eGDM)’. (3) It has been reported that the lifetime risk of progression to T2D post GDM is around 10-fold, but this is typically following cGDM.(1, 2) There is limited information on the rates of postpartum dysglycemia (prediabetes and T2D) in women diagnosed with eGDM.
Aim
To estimate the prevalence of postpartum dysglycemia [T2D, prediabetes, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT)] in women diagnosed with history of eGDM
Methods
A systematic review and meta-analysis of observational studies following up women with history of eGDM to report prevalence of postpartum dysglycemia was conducted. eGDM was defined if the GDM was diagnosed before 24 weeks of gestation. Databases including PubMed, Ovid, Embase, CINAHL, and Web of Science were searched from inception until July 2022. This identified 214 studies, 54 duplicates removed. Using Covidence, two independent reviewers (HW and SC) screened 160 abstracts stating 141 studies as irrelevant. After full text screening, 6 studies were included for meta-analysis and 13 studies were excluded. Data on rates of postpartum dysglycemia was extracted for eGDM group and comparison group wherever relevant. Meta-analysis was performed using R Studio. Findings are presented as prevalence rates and publication bias was ascertained using Egger’s test. Risk of bias was ascertained.
Findings
Postpartum screening was performed between 4 and 18 weeks in six studies that followed up women with eGDM.(4-9) About one third of women with eGDM had some degree of dysglycemia (IFG/IGT/T2D) during postpartum screening. The prevalence of T2D ranged from 0% to 26.7% while that of prediabetes ranged between 13.3% and 100.0%. The pooled prevalence of T2D (n=1072) and prediabetes (n=1072) in women with eGDM during postpartum screening was 5.0% and 27.7% respectively. Most studies employed cGDM as a comparison group for eGDM in postpartum diabetes screening. Women diagnosed with eGDM had 5.6 times (95% CI: 3.6 – 8.7) higher relative risk for conversion to T2D compared with women diagnosed with cGDM. Similarly, eGDM women had 1.9 times (95% CI: 1.4 – 2.7) higher relative risk for developing prediabetes compared to cGDM women.
Conclusion
Postpartum dysglycemia in women with eGDM is very common but more studies are needed, especially in high-risk populations like south and southeast Asia.