Metformin Use During Pregnancy

Abstract

Introduction: A commonly used first-line antidiabetic drug for type 2 diabetes mellitus is metformin. It is used with increasing frequency during pregnancy. The US Food and Drug Administration classifies it as having low teratogenic risk; however, metformin is known to have an antifolate effect similar to that of chemotherapeutic drugs.

Objective: To present the advantages and disadvantages related to the safety of the use of metformin during pregnancy.

Methods: A review of the literature was carried out based on chronological and thematic criteria, both for scientific monographs and for articles published in medical journals indexed in online databases, in Spanish and English. The Google Scholar search engine and a combination of keywords were used.

Conclusions: Although few randomized controlled trials have been conducted on fetal condition after maternal consumption of metformin during pregnancy, generally speaking, it is not considered a teratogenic drug, therefore, health professionals can prescribe it without waiting for the presence of major congenital defects at birth. However, some studies have identified an increased risk for the presence of small-for-gestational-age neonates, as well as certain folate-sensitive congenital defects in offspring, which is why preconception administration of folic acid supplements or vitamin supplements is recommended before of the prescription of metformin during pregnancy.