Pregnancy outcomes in the different phenotypes of gestational diabetes mellitus based on the oral glucose tolerance test. A systematic review and meta-analysis.

Aims: To assess the prevalence variation in pregnancy outcomes of the different phenotypes of gestational diabetes mellitus (GDM).

Materials: Cohort, cross sectional and case control studies grouping together pregnant women with GDM, based on the results of oral glucose tolerance test(OGTT) and reporting pregnancy outcomes in each group, were included. The primary outcomes were (i)large for gestational age and ii)hypertensive disorders of pregnancy (HDP). The secondary outcomes included (i)insulin treatment, ii)admission to neonatal intensive care unit, iii)preterm birth, iv)small for gestational age and v)caesarean section. The pooled proportions of the outcomes of interest were calculated for each phenotype.

Results: 8 studies (n = 20.928 women with GDM) were included. The pooled prevalence of LGA, HDP and insulin treatment were 20 %, 8 % and 24 % respectively in women with abnormal fasting plasma glucose,10 %, 6 % and 9 % respectively in women with abnormal post-load plasma glucose and 14 %,14 % and 30 % in women with abnormal combined plasma glucose.

Conclusions: Pregnant women with abnormal fasting plasma glucose, present with the highest prevalence of LGA, while those with abnormal combined plasma glucose, present with the highest prevalence of HDP. Pregnant women with abnormal post-load plasma glucose present with the lowest need for insulin treatment.