Resistin concentration and gestational diabetes: a systematic review of the literature.

Gestational diabetes (GD) exposes mothers and infants to the risk of immediate and later adverse outcomes. Increased insulin resistance is a common feature of GD and obesity. Because of its critical role in regulating insulin sensitivity, resistin has been implicated in the physiopathology of GD. The aim of this study was to review the existing literature on the relationship between circulating maternal resistin levels and GD. Three electronic databases (MEDLINE, EMBASE, and LILACS) were searched for pertinent studies published from 2001 to 2012, without language restrictions. Eleven studies, with a total of 639 participants between 23 and 41 weeks of gestation, were included. The number of GD patients per study ranged from 11 to 81, with varying degrees of disease severity and several different GD diagnostic criteria. Mean concentrations of resistin varied widely both in control women (0.05-22.21 ng/ml) and in GD patients (0.05-62.38 ng/ml). We performed a meta-analysis including a total of 10 studies, and also subgroup analyses according to gestational age at sample collection (up to 32 and >33 weeks). The pooled absolute mean difference (WMD) in resistin levels was slightly lower in GD patients than in controls, but this did not reach statistical significance (WMD=-0.02, 95% CI -0.07 to 0.04). According to the data from the 11 studies analyzed, there was no association between circulating resistin levels and GD. However, this result should be interpreted with caution owing to the large heterogeneity amongst the existing published studies.