Previous randomized and observational studies on the efficacy of metformin in pregnancy to reduce incident gestational diabetes mellitus (GDM) in women at high risk (obesity, polycystic ovary syndrome [PCOS], or pregestational insulin resistance) have been conflicting and several groups are planning further randomized controlled trials (RCTs) to answer this question conclusively. This work assesses the efficacy of metformin in pregnancy to avert one outcome—incident GDM in women at high risk. We included RCTs comparing metformin with usual care or placebo controls in terms of incident GDM and recruiting women at high risk during early pregnancy. Eleven eligible trials enrolled 2370 adult women whose intervention arm consisted of metformin started at conception or before 20 weeks of gestation. Risk of GDM was similar in intervention compared with controls (risk ratio [RR] 1.03; 95% confidence interval [CI], 0.85‐1.24). The data were of sufficient quality meeting the criteria for consistency and directness. We conclude that metformin does not contribute to averting the GDM outcome in women at high risk when initiated in pregnancy. The evidence provided by this synthesis affirms that further broad clinical trials investigating this question are no longer needed.

中文翻译：

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妊娠中的二甲双胍可避免高危女性的妊娠糖尿病：随机对照试验的荟萃分析。

先前关于妊娠二甲双胍降低高危女性（肥胖症，多囊卵巢综合征[PCOS]或孕前胰岛素抵抗）的事件性妊娠糖尿病（GDM）功效的随机和观察性研究一直存在冲突，并且一些小组正在进一步计划随机对照试验（RCT）可以最终回答这个问题。这项工作评估了二甲双胍在妊娠中避免一种结果（高危妇女发生GDM）的功效。我们纳入了随机对照试验，比较了二甲双胍与常规护理或安慰剂对照在发生GDM方面的差异，并招募了妊娠早期高危女性。共有11项合格试验纳入了2370名成年女性，这些女性的干预臂由二甲双胍组成，从受孕时开始或在妊娠20周之前开始。与对照组相比，GDM的干预风险相似（风险比[RR] 1.03； 95％置信区间[CI]为0.85-1.24）。数据具有足够的质量，可以满足一致性和直接性的标准。我们得出的结论是，二甲双胍在怀孕初期不会对避免高危妇女的GDM结局做出贡献。该综合提供的证据表明，不再需要进一步广泛的临床试验来研究该问题。