Gestational diabetes mellitus (GDM) is defined as any degree of
glucose intolerance occurring first time during pregnancy. Its prevalence is simultaneously increasing with the global rise of diabesity. GDM commonly develops, when maternal
glucose metabolism is unable to compensate for the progressive development of
insulin resistance, arising primarily from the consistently rising diabetogenic
placental hormones. It classically develops during the second or third trimester. Theoretically,
insulin sensitizers should have been the ideal agent in its treatment, given the
insulin resistance, the major culprit in its pathogenesis. Fortunately, majority of women can be treated satisfactorily with lifestyle modification, and approximately 20% requires more intensive treatment. For several decades,
insulin has been the most reliable treatment strategy and the gold standard in GDM.
Metformin is effective
insulin sensitizing agent and an established first line
drug in
type 2 diabetes currently. As it crosses the placenta, a safety issue remains an obstacle and, therefore,
metformin is currently not recommended in the treatment of GDM. Nevertheless, given the emerging clinically equivalent safety and efficacy data of
metformin compared to
insulin, it appears that it may perhaps open a rather new door in managing GDM. The aim of this review is to critically analyze, the safety and efficacy data of
metformin regarding its use in GDM and pregnant mothers with polycystic
ovarian disease, which has emerged in past decades.