Does continuous use of metformin throughout pregnancy improve pregnancy outcomes in women with polycystic ovarian syndrome?

Abstract

Aim: Polycystic ovarian syndrome (PCOS) is one of the most common endocrinopathies in women of reproductive age. It is associated with hyperinsulinemia and insulin resistance which is further aggravated during pregnancy. This mechanism has a pivotal role in the development of various complications during pregnancy. In the past few years, metformin, an insulin sensitizer, has been extensively evaluated for induction of ovulation. Its therapeutic use during pregnancy is, however, a recent strategy and is a debatable issue. At present, evidence is inadequate to support the long-term use of insulin-sensitizing agents during pregnancy. It is a challenge for both clinicians and researchers to provide good evidence of the safety of metformin for long-term use and during pregnancy. This study aimed to evaluate pregnancy outcomes in women with PCOS who conceived while on metformin treatment, and continued the medication for a variable length of time during pregnancy. Methods: This case-control study was conducted from January 2005 to December 2006 at the antenatal clinics of the Department of Obstetrics and Gynecology, Aga Khan University, Karachi, Pakistan. The sample included 137 infertile women with PCOS; of these, 105 conceived while taking metformin (cases), while 32 conceived spontaneously without metformin (controls). Outcomes were measured in three groups of cases which were formed according to the duration of use of metformin during pregnancy. Comparison was made between these groups and women with PCOS who conceived spontaneously. Results: All 137 women in this study had a confirmed diagnosis of PCOS (Rotterdam criteria). These women were followed up during their course of pregnancy; data forms were completed once they had delivered. Cases were divided into three groups: group A, 40 women who stopped metformin between 4-16 weeks of pregnancy; group B, 20 women who received metformin up until 32 weeks of gestation; and group C; 45 women who continued metformin throughout pregnancy. All the groups were matched by age, height and weight. Comparison was in terms of early and late pregnancy complications, intrauterine growth restriction and live birth rates. In groups A, B and C the rate of pregnancy-induced hypertension/pre-eclampsia was 43.7%, 33% and 13.9% respectively (P < 0.020). Rates of gestational diabetes requiring insulin treatment in groups A and B were 18.7% and 33.3% compared to 2.5% in group C (P < 0.004). The rate of intrauterine growth restriction was significantly low in group C: 2.5% compared to 19.2% and 16.6% in groups A and B respectively (P < 0.046). Frequency of preterm labor and live birth rate was significantly better in group C compared to groups A and B. Overall rate of miscarriages was 7.8%. Controls were comparable to group A in terms of early and late pregnancy complications. Conclusion: In women with PCOS, continuous use of metformin during pregnancy significantly reduced the rate of miscarriage, gestational diabetes requiring insulin treatment and fetal growth restriction. No ...

Use of metformin during pregnancy for women with polycystic ovary syndrome

“…Of the 25 trials included for this review, there were four randomised controlled trials (RCTs) [10][11][12][13], one clinical trial [14], four retrospective cohort studies [15][16][17][18], and sixteen prospective cohort studies [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. These studies were conducted globally with a large number originating from USA.…”

“…Metformin was limited to the first trimester in four trials [11,14,16,27], with the remainder continuing metformin for the entire duration of pregnancy. A comparison of continuing metformin in the first trimester and throughout pregnancy was made in four trials [10,23,26,33]. Metformin was used for fertility treatment in most participants prior to pregnancy.…”

“…Seven studies assessed the association of metformin and preterm labour in women with PCOS, of which four showed that metformin statistically reduced preterm labour rates [12,13,20,23]. One RCT showed no difference in preterm labour rates with use of metformin throughout pregnancy compared to eight weeks [10], and one retrospective study showed higher preterm rates compared to normal populations [17].…”

“…Four of these showed a statistically significant decrease in PIH with the use of metformin throughout pregnancy compared to PCOS and normal populations [15,20,21,23], while one showed an increase in PIH compared to a normal population [26].…”

“…Eleven of these studies showed statistical significance for reduced miscarriages with five studies specifically addressing EPL [15,18,25,33,34] and the remainder being unspecified [14,17,19,20,23,28]. The results of six studies were compared against the previous pregnancy results of the participants [14,17,19,28,33,34], and five were compared against control groups with PCOS [15, 18,20,23,25]. Three studies showed reduced miscarriage rates in women with recurrent pregnancy loss (RPL) [15,19,28] of which two studies combined metformin with enoxaparin [19,28].…”