Metformin is a first-line medication for the treatment of type 2 diabetes mellitus.
In recent years, research hotspots surrounding this drug have largely focused on areas such as cancer and ageing. Multiple studies have uncovered its diverse potential benefits, including anti-ageing effects, anti-tumour activity, and alleviation of autistic symptoms.
Now, a new study published in Lancet Diabetes & Endocrinology (a subsidiary journal of The Lancet) has revealed another new application of metformin: the drug can reduce the risks of late miscarriage and preterm birth among women with polycystic ovary syndrome (PCOS).
PCOS: A Major Risk Factor for Gestational Diabetes, Miscarriage and Preterm Birth
Polycystic ovary syndrome (PCOS) is a common complex endocrine and metabolic disorder affecting women of reproductive age, with a prevalence of 10–15% in the female population. Its manifestations include irregular menstruation, elevated androgen levels and ovarian follicular cysts.
Furthermore, many patients with PCOS are overweight. Their fertility may be impaired, and they face higher risks of miscarriage, gestational diabetes mellitus, preterm birth and pre-eclampsia. The exact aetiology of PCOS remains unclear, though it may be associated with lifestyle, genetics and intrauterine fetal factors.
Metformin May Halve Risks of Miscarriage and Preterm Birth
Scientists from the Norwegian University of Science and Technology (NTNU) and St. Olavs Hospital carried out a nearly 20-year study and found that women with PCOS who take metformin after the end of the third month of pregnancy may have a lower risk of subsequent miscarriage and preterm birth.
Between 2000 and 2017, the research team conducted three controlled trials involving nearly 800 pregnant women with PCOS across 15 hospitals in Norway, four hospitals in Sweden and one hospital in Iceland. Half of the participants received 2000 mg of metformin daily from early pregnancy until delivery, while the remaining women took a placebo as the control group.
The results demonstrated that this intervention lowered the risks of late miscarriage and preterm birth in pregnant women with PCOS. Meanwhile, women receiving metformin experienced less gestational weight gain.
Unexpected Outcome: No Benefit Against Gestational Diabetes
However, to the team's surprise, metformin use did not reduce the incidence of gestational diabetes mellitus among these PCOS participants. Additionally, metformin exerted no significant effects on pre-eclampsia, gestational hypertension, or the need for neonatal intensive care unit admission.
Professor Eszter Vanky, author of the paper, stated that the most striking finding is that metformin fails to prevent gestational diabetes. As a classic drug for type 2 diabetes, metformin is regarded as a first-line therapy comparable to insulin for gestational diabetes in some countries. Nevertheless, this latest study yields negative evidence against such practice.
