Mid-pregnancy fetal growth, uteroplacental Doppler indices and maternal demographic characteristics: role in prediction of stillbirth.

Abstract

To evaluate the relative value of mid trimester fetal growth, uterine artery Doppler indices and maternal demographics in prediction of stillbirth. Retrospective cohort study; 23894 singleton pregnancies routinely scanned between 19 and 24weeks' gestation. Maternal characteristics included age, body mass index, ethnicity and medical history. Fetal biometry indices, birthweight and uterine artery pulsatility index values were converted to percentiles and multivariable logistic regression analysis was performed. The predictive accuracy was assessed using receiver operating characteristic curves analysis. The main outcome was prediction of preterm and term stillbirths. Non-Caucasian ethnicity, femur length centile and uterine artery pulsatility index were significantly associated with the risk of stillbirth (all p<0.01). The detection rate of screening by maternal factors alone was 19% for all stillbirths, and 12 and 14% for term and preterm stillbirth at a 10% false positive rate, respectively. Using femur length centile alone, the detection rates were 27 and 23%, respectively. Uterine artery pulsatility index alone was able to predict 24 and 31% of term and preterm stillbirths. Screening by combining maternal factors, femur length centile and uterine artery Doppler detected 27 and 35% of term and preterm stillbirths at a 10% false positive rate. Second trimester ultrasound assessment offers an opportunity to identify pregnancies at the highest risk of stillbirth occurring as a consequence of placental dysfunction. This information may be useful to improve pregnancy outcome by identifying women who may benefit from increased ultrasound surveillance and/or timely intervention.