Relationship between abnormal glucose tolerance test and history of previous recurrent miscarriages, and beneficial effect of metformin in these patients: a prospective clinical study

ObjectiveTo determine the incidence of an abnormal glucose tolerance test in patients with recurrent spontaneous abortion and whether metformin would safely reduce the rate of first trimester spontaneous abortions in patients without polycystic ovary syndrome (PCOS) as well as with PCOS and an abnormal glucose tolerance test.DesignProspective control clinical trial.SettingShiraz University-affiliated hospital.Patient(s)Patients with a history of recurrent spontaneous abortion and women with a history of normal full term pregnancy.Intervention(s)The incidence of abnormal carbohydrate metabolism was determined. Metformin and placebo were given to women with an abnormal glucose tolerance test and who had recurrent spontaneous abortions.Main Outcome Measure(s)Continuation of pregnancy beyond the first trimester in all groups and presence or absence of teratogenicity in the delivered baby after metformin therapy.Result(s)Twenty-nine of the patients in the group with recurrent spontaneous abortion were found to have an abnormal glucose tolerance test result compared with just four (5.4%) patients in the normal pregnancy group. The abortion rate was significantly reduced after metformin therapy in patients without PCOS in comparison to the placebo group (15% vs. 55%).Conclusion(s)This study indicates an important link between an abnormal glucose tolerance test and a history of recurrent abortion. It was also found that metformin therapy improves the chances of a successful pregnancy in patients with an abnormal glucose tolerance test.