Angiogenic and fibrinolytic factors in blood during the first half of pregnancy and adverse pregnancy outcomes.

Objective: To estimate whether the imbalance of angiogenic factors (soluble fms-like tyrosine kinase-1, placental growth factor) and fibrinolytic factors (plasminogen activator inhibitor-2 [PAI-2]) might affect placentation in early pregnancy.

Methods: We studied the associations of maternal soluble fms-like tyrosine kinase-1, placental growth factor, and PAI-2 concentrations in the first trimester (before 18 weeks of gestation) and soluble fms-like tyrosine kinase-1 and placental growth factor concentrations in the second trimester (18-25 weeks of gestation) with placental function and adverse pregnancy outcomes. This study was embedded in a population-based prospective cohort study. Data were used from 7,519 women. Biomarker concentrations were divided into deciles and evaluated in multivariable linear and logistic regression models.

Results: First-trimester high soluble fms-like tyrosine kinase-1 was associated with a 5.2% lower uterine artery index in the second-trimester and a 1.6% higher birth weight (55 g, confidence interval [CI] 15-95). Neither in the first nor in the second trimester were soluble fms-like tyrosine kinase-1 concentrations significantly associated with preeclampsia. First-trimester low placental growth factor was associated with a 6.1% higher uterine artery index and a 3.4% lower birth weight (-115 g, CI -157 to -74). First-trimester low placental growth factor was associated with fetal growth restriction (odds ratio [OR] 2.62, CI 1.68-4.08) and preeclampsia (OR 2.46, CI 1.49-4.08). First-trimester low PAI-2 was associated with a 1.9% higher uterine artery index and a 2.7% lower birth weight (-94 g, CI -136 to -51). First-trimester low PAI-2 was associated with a higher risk of fetal growth restriction (OR 2.22, CI 1.39-3.55).

Conclusion: First-half-of-pregnancy concentrations of soluble fms-like tyrosine kinase-1, placental growth factor, and PAI-2 are associated with uteroplacental vascular resistance, placental weight, and birth weight. Moreover, first-trimester placental growth factor and PAI-2 are associated with an increased risk of adverse pregnancy outcomes.

Level Of Evidence: II.