Introduction
Preeclampsia (PE) affects 2-3 % of all gestations globally; although mortality due to PE is uncommon in high-resourced countries, morbidity is high1. The overall burden of adverse outcomes associated with preeclampsia is considerable; close antenatal surveillance and timely interventions can prevent these adverse outcomes.
Angiogenesis is essential for embryonic development and growth and is regulated by a complex interplay of a numerous factors. Placental growth factor (PlGF) is a glycoprotein synthesized in villous and extra-villous cytotrophoblasts, and is the most validated and studied biomarker of PE screening. Its function is angiogenesis and assistance in trophoblastic invasion of the maternal spiral arteries, thus maintaining the placental oxygenation2. The strategy of early pregnancy universal screening of all women with PlGF, mean arterial pressure and uterine artery Doppler for the detection of PE has been accepted now. Those who are found to be at high risk need to be started on aspirin, but although the prevention rate of early onset PE is close to 90%, the late onset preeclampsia can be prevented in just over half of the women on aspirin, hence vigilance in the latter half of pregnancy is needed even if the women are on aspirin 3.
In the high-risk women who are booked late in pregnancy, screening and risk stratification can modify their antenatal surveillance, consequently, avoiding long term hospitalization and frequent hospital visits if they are deemed low risk. The use of sFLT-1/PlGF ratio has also proved to be a very effective marker 4,5,6 ,but using both sFLT-1 and PlGF for the assessment of risk, doubles the cost of the test. PlGF levels have been seen to decrease many weeks before the onset of PE, with a substantial decrease five weeks before its onset5.
Though the usefulness of PlGF alone as a biomarker in early pregnancy is established 4, its use in the latter half of pregnancy has not been fully explored, especially with respect to the timing of the test and its cut-offs at particular gestation. Hence, the study was designed to evaluate the predictive value of the angiogenic biomarker PlGF for likelihood of adverse perinatal and maternal outcomes among high-risk women. We also wanted to find out the gestational age-specific cut-off of PlGF in the second half of pregnancy.