We found limited evidence to evaluate early screening for GDM prior to 24 weeks gestation, the purpose of which would be to detect previously unrecognized diabetes (GDM is defined as onset or first recognition of diabetes during pregnancy). Therefore, more research is needed before this question can be evaluated.
A recent good-quality randomized controlled trial reported that treatment of screen-detected women with mild GDM diagnosed after 24 weeks gestation reduces both maternal and composite neonatal health outcomes, without apparent harm—as reported in this RCT and in several other observational studies.