Association of first trimester serum uric acid with preeclampsia: an observational cohort study with propensity score matching

To elucidate whether uric acid changes in early pregnancy are associated with the development of preeclampsia and their association with preeclampsia-related adverse pregnancy outcomes. We conducted a retrospective cohort study of 4725 singleton pregnant women between January 2017 and July 2019 using propensity score matching. The primary outcome of the cohort was preeclampsia, and the secondary outcomes were preterm delivery, preterm preeclampsia and low birth weight infants. Multivariable predicted marginal proportions from logistic regression models were used to compute adjusted risk ratios. The quantitative-effect relationship between serum uric acid and preeclampsia development was observed by a dose‒response graph, and the effect of serum uric acid on the week of gestation at delivery was assessed using the Kaplan‒Meier method and the log-rank test. The risk of preeclampsia development increased with higher serum uric acid levels. After adjusting for confounders, the risk ratio for the development of preeclampsia with uric acid levels ≥240 µmol/l was 1.25 (95% CI: 0.96–1.65) compared with the group with uric acid levels <240 µmol/l. In the subgroup analysis of KM (Kaplan–Meier) curves, the gestational week at delivery was earlier when uric acid levels ≥240 µmol/l occurred at 8–12 weeks of gestation. Elevated serum uric acid levels before 20 weeks of gestation are associated with the development of preeclampsia, especially in the first 8–12 weeks of gestation, and the effect is attenuated with increasing gestational weeks, which suggests that elevated uric acid levels in early pregnancy may be a causative factor in preeclampsia.