Objectives: To investigate whether measurement of maternal serum placental growth factor (PLGF) at 19-24 weeks’ gestation improves the performance of screening for stillbirths that is achieved by a combination of maternal factors, fetal biometry and uterine artery pulsatility index (UT-PI) and evaluate the performance of screening of this model for all stillbirths and those due to impaired placentation and unexplained or other causes.
Methods: This was a prospective screening study of 70,003 singleton pregnancies including 268 stillbirths, carried out in two phases. The first phase, which included prospective measurements of UT-PI and fetal biometry were available in all cases. The second phase included prospective measurements of maternal serum PLGF which were available for 9,870 live births and 86 antepartum stillbirths. The values of PLGF obtained from this screening study were simulated in the remaining cases based on bivariate Gaussian distributions, defined by the mean and standard deviations. Multivariate logistic regression analysis was used to determine whether the addition of maternal serum PLGF improved the performance of screening that was achieved by a combination of maternal factors, fetal biometry and UT-PI.
Results: Significant contribution to the prediction of stillbirths was provided by maternal factor derived a priori risk, MoM values of PLGF, UT-PI and fetal biometry Z-scores. A model combining these variables predicted 58% of all stillbirths and 84% of those due to impaired placentation, at false positive rate of 10%; within the impaired placentation group the detection rate of stillbirth at 37 weeks (97% vs 61%; p<0.01).
Conclusions: A high proportion of stillbirths due to impaired placentation can be effectively identified in the second trimester of pregnancy
