PE is a pregnancy complication that causes high blood pressure, kidney damage, and other problems.
It refers to the onset of hypertension with proteinuria and/or end-organ dysfunction after 20 weeks of gestation in a previously normotensive woman.
The clinical manifestations of PE can appear any time from the late second trimester to the first few weeks postpartum. The condition stems in early pregnancy and is characterised by abnormal remodeling of the maternal spiral arteries at the placental site.
Early diagnosis may improve maternal and perinatal outcome by ensuring appropriate management (eg, antenatal corticosteroids for fetal lung maturation, treatment of severe hypertension, and early delivery).
The best ways of predicting PE involve multiparametric approaches, using a variety of parameters in combination (such as established in first-trimester aneuploidy screening). A combination of maternal risk factors, the uterine artery pulsatility index (PI), mean arterial pressure (MAP), and maternal serum pregnancy-associated plasma protein-A (PAPP-A), placental growth factor (PlGF), PP13, and fetal haemoglobin levels at 11-13 weeks’ gestation can be used to identify a high proportion of pregnancies at high risk for early onset PE.
Research shows that angiogenic markers are useful in diagnosis aa well as prediction and management of PE and placenta-related disorders. PlGF circulates free or in complexes with fms-like tyrosine kinase-1. PlGF in screening for PE is used for early onset disease.
Defective early placentation with impaired trophoblast invasion and restricted remodeling of the spiral arteries are central to early-onset PE, resulting in reduced uteroplacental perfusion. The combination of second- and third-trimester sFlt-1/PlGF ratios gives a detection rate of 87% at a fixed false-positive rate of 10% for early prediction of PE in a low-risk population.
PAPP-A is a large highly glycosylated protein that is produced by developing trophoblast cells. It has been shown to be a syncytiotrophoblast-derived, insulin-like growth factor binding protein protease. The insulin-like growth factor system is believed to play an important role in placental growth and development. So, low serum PAPP-A levels are associated with a higher incidence of PE. Increased maternal serum PAPP-A levels have been observed in established PE.
Predictive models for estimating individualised risk estimates for late-onset PE are based on a combination of first-trimester levels of PAPP-A and the second-trimester sFlt-1/PlGF ratio (detection rate of 87% at a fixed false-positive ratio of 5%).
In pregnancies with development of PE, the maternal serum concentrations of PlGF and PAPP-A are reduced. These proteins are produced by the trophoblast, and their reduced maternal serum concentrations presumably reflect impaired placentation.
References available on request.