Predictive performance for placental dysfunction related stillbirth of the competing risks model for...

To examine the predictive performance for placental dysfunction related stillbirths of the competing risks model for small-for-gestational-age (SGA) fetuses based on a combination of maternal risk factors, estimated fetal weight (EFW) and uterine artery pulsatility index (UtA-PI); and second, to compare the performance of this model with that of a stillbirth-specific model using the same biomarkers and with the Royal College of Obstetricians and Gynecologists (RCOG) guideline for the investigation and management of the SGA fetus.

Prospective observational study.

Two UK maternity hospitals.

A total of 131 514 women with singleton pregnancies attending for routine ultrasound examination at 19-24 weeks of gestation.

The predictive performance for stillbirth achieved by three models was compared.

Placental dysfunction related stillbirth.

At 10% false-positive rate, the competing risks model predicted 59%, 66% and 71% of placental dysfunction related stillbirths, at any gestation, at <37 weeks and at <32 weeks, respectively, which were similar to the respective figures of 62%, 70% and 73% for the stillbirth-specific model. At a screen positive rate of 21.8%, as defined by the RCOG guideline, the competing risks model predicted 71%, 76% and 79% of placental dysfunction related stillbirths at any gestation, at <37 weeks and at <32 weeks, respectively, and the respective figures for the RCOG guideline were 40%, 44% and 42%.

The predictive performance for placental dysfunction related stillbirths by the competing risks model for SGA was similar to that of the stillbirth-specific model and superior to that of the RCOG guideline.

The competing risks approach for SGA is superior to the RCOG guideline in the prediction of placental dysfunction related stillbirths.