Maternal lipid levels during pregnancy and gestational diabetes: a systematic review and meta-analysis

Background Lipid levels during pregnancy in women with gestational diabetes mellitus (GDM) have been extensively studied; however, it remains unclear whether dyslipidaemia is a potential marker of preexisting insulin resistance. Objective To evaluate the relationship between lipid measures throughout pregnancy and GDM. Search strategy We searched PubMed-MedLine and SCOPUS (inception until January 2014) and reference lists of relevant studies. Selection criteria Publications describing original data with at least one raw lipid (total cholesterol, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], or triglyceride) measurement during pregnancy in women with GDM and healthy pregnant controls were retained. Data collection and analysis Data extracted from 60 studies were pooled and weighted mean difference (WMD) in lipid levels was calculated using random effects models. Meta-regression was also performed to identify sources of heterogeneity. Main results Triglyceride levels were significantly elevated in women with GDM compared with those without GDM (WMD 30.9, 95% confidence interval [95% CI] 25.4–36.4). This finding was consistent in the first, second and third trimesters of pregnancy. HDL-C levels were significantly lower in women with GDM compared with those without GDM in the second (WMD −4.6, 95% CI −6.2 to −3.1) and third (WMD −4.1, 95% CI −6.5 to −1.7) trimesters of pregnancy. There were no differences in aggregate total cholesterol or LDL-C levels between women with GDM and those without insulin resistance. Author's conclusions Our meta-analysis shows that triglycerides are significantly elevated among women with GDM compared with women without insulin resistance and this finding persists across all three trimesters of pregnancy.