Early pregnancy triglycerides and blood pressure: a combined predictor for preeclampsia

Increased blood pressure and triglyceride (TG) levels are linked to adverse pregnancy outcomes. Although the widespread acknowledgment that stage 2 hypertension serves as a significant predictor of preeclampsia, the prognostic significance of elevations in other blood pressure categories remains a subject of debate. Consequently, we intended to evaluate the joint influence of increased blood pressure and TG levels in the initial stages of pregnancy on preeclampsia risk and to identify a high-risk subgroup of individuals who require clinical attention.

We conducted a retrospective cohort study including 78,016 individuals with singleton births at the Shanghai International Peace Maternity and Child Health Hospital (IPMCH) between January 2014 and December 2019. The study was approved by the IPMCH Institutional Review Board. Patients were classified into four groups on the basis of blood pressure readings taken during early stages of pregnancy: normotensive, elevated, stage 1 hypertension and stage 2 hypertension, stratified by TG levels (below or above the 90th percentile). Analysis using generalized additive models and logistic regression models was conducted to investigate the relationships among blood pressure, TG levels, and preeclampsia risk.

Among the 78,016 patients, 2,204 (2.83%) developed preeclampsia. Multivariate logistic regression revealed that both stage 1 and stage 2 hypertension in early stages of pregnancy markedly increased preeclampsia risk (adjusted odds ratio (AOR), 3.40 [95% CI, 3.05-3.80]; AOR, 6.96 [95% CI, 6.15-7.88]). Generalized additive models revealed that high TG levels significantly increased the probability of preeclampsia as blood pressure increased. Stratification by blood pressure and TG levels revealed that patients with high TG levels and stage 1 or 2 hypertension exhibited a significantly greater risk of preeclampsia when compared to those with normotensive and reference TG levels, with AORs of 5.52 (95% CI, 4.61-6.62) and 10.13 (95% CI, 8.23-12.46), respectively. Interaction analysis showed stage 1 hypertension and high TG demonstrated a 1.5-fold synergistic risk of preeclampsia (OR = 1.50, P = 0.021).

The combination of increased blood pressure and high TG levels, especially high TG levels, which coincide with stage 1 or stage 2 hypertension, markedly heightened preeclampsia risk. Our findings indicate that the co-occurrence of stage 1 hypertension with high TG levels should be regarded as a notable risk factor for preeclampsia, approaching the risk level associated with stage 2 hypertension alone.