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.