Polycystic ovary syndrome and metformin in pregnancy

The diagnostic criteria of polycystic ovary syndrome incorporate hyperandrogenism, polycystic ovaries, anovulation and irregular menstrual bleeding and the syndrome is a recognized reason behind infertility. The biguanide metformin has encouraging effects on several metabolic aspects of the syndrome, including insulin sensitivity, plasma glucose concentration and lipid profile. Moreover, metformin improves the ovarian function in women diagnosed with polycystic ovary syndrome. Hence, metformin is considered an agent for ovulation induction among these patients. However, even higher ovulation frequencies have been observed when metformin has been adjuvant to clomifene therapy. Metformin-induced ovulation presumably brings about resumption of regular menstrual cycles and improved conception rates. Polycystic ovary syndrome patients are presumably more likely than healthy women to suffer from pregnancy-related problems like early pregnancy loss, gestational diabetes mellitus and hypertensive states in pregnancy. Recent data suggest sparing effects of continued metformin therapy throughout pregnancy on early pregnancy loss and gestational diabetes mellitus, but its impact on hypertensive complications to pregnancy appears less evident. Instead, metformin might even induce pre-eclampsia or exert no effect on blood pressure.

So far, evidence for safety of continued therapy throughout gestation is insufficient, and existing papers are limited in design and might mask for fetal toxic outcomes due to metformin therapy. Prior to a recommendation of sustained metformin therapy throughout pregnancy, randomized placebo-controlled double-blinded clinical trials are awaited with interest, so that present assumptions on efficiency can be clarified, in order to assure efficient and safe management of pregnant polycystic ovary syndrome patients.