BACKGROUND: Maternal retinol-binding protein 4 (RBP4) and lipids may relate to preeclampsia and preterm birth risk but longitudinal data are lacking. This study examines these biomarkers longitudinally during pregnancy in relation to preeclampsia and preterm birth risk. METHODS: Maternal serum samples from the Calcium for Preeclampsia Prevention (CPEP) trial were analyzed at baseline: average 15 gestational weeks; mid-pregnancy: average 27 weeks; and at >34 weeks. We measured RBP4, total cholesterol, high-density lipoprotein, low-density lipoprotein, triglycerides and lipoprotein (a) (Lp(a)). Cross-sectional logistic regression analyses estimated the odds ratio (OR) and 95% confidence intervals (CI) for preterm preeclampsia (n = 63), term preeclampsia (n = 104), and preterm delivery (n = 160) associated with RBP4 and lipids at baseline and mid-pregnancy compared with controls (n = 136). Longitudinal trajectories across pregnancy were assessed using mixed linear models with fixed effects. Adjusted models included clinical and demographic factors. RESULTS: RBP4 concentrations at baseline and mid-pregnancy were associated with a 4- to 8-fold increase in preterm preeclampsia risk but were not associated with term preeclampsia. RBP4 measured mid-pregnancy was also associated with preterm birth (OR = 6.67, 95% CI: 1.65, 26.84). Higher triglyceride concentrations in mid-pregnancy were associated with a 2- to 4-fold increased risk for both preeclampsia and preterm birth. Longitudinal models demonstrate that both preterm preeclampsia and preterm birth cases had elevated RBP4 throughout gestation. CONCLUSIONS: Elevated RBP4 is detectable early in pregnancy and its strong relation with preterm preeclampsia merits further investigation and confirmation to evaluate its potential use as a predictor, particularly among high-risk women.
Bibliographical noteFunding Information:
This research was supported by the Intramural Research Program of Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The manuscript has been cleared by NICHD for publication but the funding source had no role in the study design; in the collection, analysis, and interpretation of data; or in the writing of the report. The Calcium for Preeclampsia Prevention trial was supported by contracts (N01-HD-1-3121, -3122, -3123, -3124, -3125, and -3126; N01-HD-3154; and N01-HD-5-3246) with the NICHD, with co-funding from the National Heart, Lung, and Blood Institute. Recent biomarker assays, including retinol-binding protein 4, was supported by contract (HHSN275201100002I-HHSN27500003) with NICHD.
- Blood pressure
- Preterm birth
- Retinol-binding protein 4