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.