Placental growth factor testing reduces time to diagnosis for women with suspected pre-eclampsia

Pre-eclampsia is a condition that affects approximately 2–8% pregnancies worldwide and, although the cause is not really understood, is thought to be due to poor function of the placenta. Early signs that create suspicion of pre-eclampsia in the mother typically include hypertension, proteinuria and edema (particularly of the pitting type) of the ankles. Symptoms of more severe pre-eclampsia can include pulmonary edema, headaches, visual disturbance, epigastric/right upper quadrant abdominal pain and vomiting, before the development of seizures (eclampsia). Symptoms in the fetus include fetal growth restriction.
Left untreated, pre-eclampsia is associated with a high risk of adverse outcome for both the mother and fetus. The only treatment is delivery of the baby and the placenta. Diagnosis of pre-eclampsia is challenging because of the vagueness of the symptoms, but becomes suspected with new onset hypertension after 20 weeks’ gestation. The management of women presenting with pre-eclampsia from 37 weeks of gestation is through planned delivery. However, the management of patients with suspected pre-eclampsia earlier in pregnancy involves careful surveillance, and therefore increased use of health resources, balancing the risk to maternal health against the risk of preterm delivery for the fetus. Angiogenic factors, such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) have shown potential for the diagnosis of pre-eclampsia in cohort studies. Recently, however, the results of study using a stepped-wedge cluster-randomized controlled trial measuring PlGF levels alongside the use of a clinical management algorithm have been published in The Lancet (Duhig KE, et al. Lancet 2019; pii: S0140-6736(18)33212-4). The study involved more than 1000 women with suspected pre-eclampsia and the women were divided into two groups – where the PlGF levels were either made known (revealed PlGF) or not (concealed PlGF). The results showed that in the revealed PlGF group, time to diagnosis fell from 4.1 to 1.9 days compared with the concealed PlGF group and that serious maternal complications fell from 5.3% (24 of 447 women) to 4% (22 of 573 women). The findings from the study, have resulted in NHS England deciding to make the test more widely available, allowing more timely patient management and more appropriate use of resources in high-risk women, so helping to avoid life-threatening complications for both mother and baby as well as providing reassurance when
pre-eclampsia is ruled out.