Impacts of maternal lipid and homocysteine levels on the risks of pregnancy complications and adverse outcomes in both singleton and twin pregnancies: a population-based observational cohort study

In pregnancy, there is a lack of consensus on reference intervals (RIs) of serum lipids and homocysteine (Hcy) to guide clinical intervention. This population-based cohort study aimed to establish trimester-specific reference intervals of serum lipids and Hcy, and to reveal the associations between maternal lipid profiling and adverse outcomes during pregnancy. The laboratory test results of Hcy and lipid profile, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C), were collected from 29,380 singleton and 840 twin pregnant women who had their regular antenatal check-ups between October 1st, 2017 and September 30th, 2019. The trimester-specific RIs of lipids and Hcy were established using both the nonparametric approach and the indirect Hoffmann method, followed by the outcome logistic association analysis. There was no significant difference between the observed RIs estimated with healthy pregnant women and the calculated RIs derived from the Hoffmann method (all p > 0.05). The maternal Hcy level was positively associated with the risk of preterm birth (PTB)with adjusted OR values ranged from 1.10 (95% CI 0.97–1.24) to 1.48 (95% CI 1.02–2.14) in the first trimester and from 1.63 (95% CI 1.44–1.83) to 3.46 (95% CI 2.65–4.52) in the third trimester, but negatively associated with the risk of gestational diabetes mellitus (GDM)with OR values ranged from 0.70 (95% CI 0.56–0.88) to 0.81 (95% CI 0.62–1.07). High levels of TC, TG, LDL-C and low level of HDL-C were found to be associated with increased risks in GDM, PTB, postpartum hemorrhage(PPH), intrahepatic cholestasis of pregnancy(ICP) (all OR > 1, p < 0.05). Our study established trimester-specific RIs of serum lipids and Hcy in both singleton and twin pregnancies, which have important clinical and research value for pregnancy health management and adverse outcome prevention.