Personalized stratification of pregnancy care for small for gestational age neonates from biophysical markers at mid-gestation

Antenatal identification of pregnancies at high-risk to deliver small for gestational age (SGA) neonates, may improve the management of the condition and reduce the associated adverse perinatal outcome. In a series of publications we have developed a new competing risks model for SGA prediction and we demonstrated that the new approach has a superior performance to that of the traditional methods. The next step in shaping the appropriate management of SGA is the timely assessment of these high-risk pregnancies according to an antenatal stratification plan. To demonstrate the stratification of pregnancy care based on individual patient risk derived from the application of the competing risks model for SGA that combines maternal factors with sonographic estimated fetal weight (EFW) and uterine artery pulsatility index (UtA-PI) at mid-gestation. This was a prospective observational non-intervention study in 96,678 women with singleton pregnancies undergoing routine ultrasound examination at 19-24 weeks of gestation, which included recording of EFW and measurement of UtA-PI. The competing risk model for SGA was used to create a patient specific stratification curve capable to define a specific timing for a repeat ultrasound examination after 24 weeks. We examined different stratification plans with the intention of detecting about 80%, 85%, 90% and 95% of SGA neonates with birth weight <3 and <10 percentiles at any gestational age at delivery until 36 weeks; all pregnancies would be offered a routine ultrasound examination at 36 weeks. The stratification of pregnancy care for SGA can be based on a patient specific stratification curve. Factors from maternal history, low EFW and increased UtA-PI shift the personalized risk curve towards higher risks. The degree of shifting defines the timing for assessment for each pregnancy. If the objective of our antenatal plan was to detect 80%, 85%, 90% and 95% of SGA neonates at any gestational age at delivery until 36 weeks, the median (range) proportions (%) of population examined per week would be 3.15 (1.9, 3.7), 3.85 (2.7, 4.5), 4.75 (4.0, 5.4) and 6.45 (3.7, 8.0) for SGA < 3 percentile and 3.8 (2.5, 4.6) ,4.6 (3.6, 5.4), 5.7 (3.8, 6.4) and 7.35 (3.3, 9.8) for SGA < 10 percentile, respectively. The competing risks model provides an effective personalized continuous stratification of pregnancy care for SGA which is based on the individual characteristics and the biophysical marker levels recorded at the mid-gestation scan. [Abstract copyright: Copyright © 2022. Published by Elsevier Inc.]