Serum PlGF compared with PAPP‐A in first trimester screening for preterm pre‐eclampsia: Adjusting for the effect of aspirin treatment

Abstract Objective To compare the predictive performance for preterm‐pre‐eclampsia (PE) in first‐trimester screening by serum placental growth factor (PlGF) versus pregnancy associated plasma protein‐A (PAPP‐A), in combination with maternal risk factors, mean arterial pressure (MAP) and uterine artery pulsatility index (UtA‐PI), after adjustment for the effect of aspirin in women receiving this treatment. Design Non‐intervention multicentre screening studies for PE in singleton pregnancies. Setting Maternity hospitals. Population Two independent prospective studies of 8775 and 16 451 women with singleton pregnancies attending for routine assessment at 11 +0 –13 +6 weeks' gestation. Methods The competing risks model was used to estimate patient‐specific risks of delivery with PE at <37 weeks' gestation based on maternal risk factors and combinations with MAP, UtA‐PI and either PlGF or PAPP‐A. McNemar's test was used to compare the detection rate (DR) of preterm‐PE of screening utilising PlGF versus PAPP‐A, after adjustments for the effects of aspirin. Main outcome measure Predictive performance for preterm‐PE. Results In the combined data of 25 226 women, including 678 (2.7%) who developed PE, there were 194(0.8%) with preterm‐PE. Addition of PlGF improved the DR of preterm‐PE, at 10% screen positive rate, by 18.4% (95% CI 12.2–24.6) in screening by maternal risk factors, by 19.9% (95% CI 13.6–26.2) in screening by maternal factors and MAP, and by 7.0% (95% CI 2.3–11.6) in screening by maternal factors, MAP and UtA‐PI. PAPP‐A did not significantly improve the DR provided by any combination of biomarkers. Conclusion The predictive performance of first trimester PlGF for preterm‐PE is superior to that of PAPP‐A.