Urinary Placental Growth Factor For Prediction Of Placental Adverse Outcomes In High-Risk Pregnancies

OBJECTIVE: To evaluate whether urinary levels of placental growth factor (PIGF) during pregnancy are associated with the subsequent development of composite adverse outcomes (preeclampsia, fetal growth restriction, placental abruption, perinatal death, maternal death) occurring at less than 34 weeks of gestation.METHODS: This is a preplanned ancillary study of the Heparin-Preeclampsia trial, a randomized trial in pregnant women with a history of severe early-onset preeclampsia (less than 34 weeks of gestation). In the parent study, all women were treated with aspirin and then randomized to receive either low-molecular-weight (LMW) heparin or aspirin alone. For this substudy we measured urinary levels of PIGF and urinary creatinine at the following gestational windows: 10-13 6/7, 14-17 6/7, 18-21 6/7, 22-25 6/7, 26-29 6/7, 30-33 6/7, and 34-37 6/7 weeks of gestation.RESULTS: Urine samples were available from 187 patients: LMW heparin plus aspirin (n=93) and aspirin alone (n=94). The two groups had comparable baseline characteristics and had similar adverse composite outcomes at less than 34 weeks of gestation (14/93 [15.1%] vs 11/94 [11.7%]; P=.50). There were no significant differences in urine PIGF levels in the patients who received LMW heparin plus aspirin compared with those who received aspirin alone. However, median [interquartile range] urinary PIGF/creatinine concentrations (pg/mg) measured at mid-pregnancy (22-26 weeks of gestation) were significantly lower among women who developed composite adverse outcome at less than 34 weeks of gestation (42.7 [32.4-80.8] vs 255.6 [118.7-391.8] P<.001) and significantly lower among women who developed preeclampsia at less than 34 weeks of gestation (42.7 [27.5-80.7] vs 244.6 [112.9-390.6] P<.001). For a fixed false-positive rate of 10% the sensitivity of urinary PIGF concentrations at midpregnancy was 75.2% (area under the curve 0.93) for the subsequent development of composite adverse outcomes.CONCLUSION: Decreased urinary PIGF at midgestation (22-26 weeks of gestation) is associated with the subsequent development of preeclampsia-related adverse outcomes at less than 34 weeks of gestation.