Pre-eclampsia, gestational hypertension, and lipid levels during pregnancy: a systematic review and meta-analysis

Gestational hypertension (GH) and pre-eclampsia (PE) are common high-risk complications of pregnancy, and are also one of the important causes of global maternal mortality and perinatal mortality. It has been suggested that abnormal lipid metabolism may play a key role in the pathogenesis of GH and PE. However, the results of different studies are controversial and lack of systematic quantitative analysis.

The aim of this study is to evaluate the differences in lipid levels between patients with GH and PE and healthy controls by meta-analysis, and to explore the potential role of abnormal lipid metabolism in the disease.

In this study, PubMed, EMBASE, Cochrane Library, CNKI, and other Chinese and English databases were searched. The subjects included in the study were patients with hypertensive disorders during pregnancy (including GH and pre-eclampsia) and healthy controls. To evaluate the differences in triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels by systematic review and meta-analysis. Revman software was used to calculate the standardized mean difference (SMD) and its 95% confidence interval (CI). Heterogeneity was evaluated by I² statistic and Q test. Publication bias and sensitivity analysis were also performed.

(1) A total of 5 studies were included in the meta-analysis of gestational hypertension and lipid profile during pregnancy, including 321 patients with gestational hypertension and 1171 healthy pregnant women. A total of 7 studies were included in the meta-analysis, including 1114 women with gestational hypertension and 32,537 healthy pregnant women. (2) The results showed that HDL levels in patients with gestational hypertension were significantly lower than those in the control group (SMD = - 0.20, 95% CI - 0.35 to - 0.06, P = 0.006), while LDL (SMD = 1.40, 95% CI 1.22 to 1.59, P < 0.00001), TC (SMD = 0.37, 95% CI 0.23 to 0.51, P < 0.00001), and TG (SMD = 0.64, 95% CI 0.50 to 0.79, P < 0.00001) were significantly elevated. (3) HDL levels were significantly lower in the pre-eclampsia group than in the control group (SMD = -0.30 mmol/L, 95% CI - 0.36, - 0.11, P < 0.00001), while LDL (SMD = 0.25, 95% CI 0.18, 0.31, P < 0.00001), TC (SMD = 0.27 mmol/L, 95% CI 0.21, 0.22, P < 0.00001) and TG (SMD = 1.15, 9% CI 0.55, 1.74, P = 0.0002) were significantly increased. Heterogeneity analysis showed moderate-to-high heterogeneity in some indicators (I² range: 56-99%). No significant bias was found in the publication bias test, and the results were robust.

This study suggests that abnormal lipid metabolism may be an important feature of GH and pre-eclampsia, suggesting that dynamic monitoring of lipid levels has clinical value for early prediction and management of the disease. The decrease of HDL level may impair the vascular protective function, and the increase of LDL, TC, and TG levels may aggravate endothelial dysfunction and oxidative stress, thereby affecting placental perfusion function.