PlGF (Placental Growth Factor) Testing in Clinical Practice: Evidence From a Canadian Tertiary Maternity Referral Center

Abstract

There is little evidence evaluating angiogenic growth factor testing in real-world obstetric settings. This investigation evaluated maternal and perinatal pregnancy outcomes associated with maternal PlGF (placental growth factor) levels in real-world clinical care of high-risk pregnancies. From March 2017 to December 2019, 979 pregnant women with suspected risk of placental dysfunction, hypertensive disorders of pregnancy, or fetal growth restriction completed PlGF testing between 20+0 and 35+6 weeks of gestation. Maternal, fetal, and delivery characteristics were extracted through the electronic medical record system. The primary outcome of preterm birth was assessed using Royston-Parmar survival models and summarized with Kaplan-Meier methods. Of the 979 pregnant women, 289 had low PlGF levels (29.5%), and 690 had normal PlGF levels (70.5%). The survival probability of ongoing pregnancy free from preterm birth within 2- and 4-weeks following PlGF testing was significantly reduced in women with low PlGF levels, relative to women with normal PlGF levels (0.57 versus 0.99, standardized survival difference, -0.43 [95% CI, -0.76 to -0.09], and 0.37 versus 0.99, standardized survival difference, -0.62 [95% CI -0.87 to -0.38], respectively). Women with low PlGF levels were more likely to develop early-onset preeclampsia (adjusted odds ratio, 58.2 [95% CI, 32.1-105.4]) and have a stillbirth (adjusted odds ratio, 15.9 [95% CI, 7.6-33.3]). PlGF status distinguished placental from fetal causes of stillbirth. Low PlGF levels in high-risk pregnant women are strongly associated with increased rates of imminent preterm birth, as well as related adverse outcomes, including early-onset preeclampsia and stillbirth.