Screening for birth weight deviations by second and third trimester ultrasound scan

Area of Science:

• Maternal-fetal medicine
• Prenatal diagnostics
• Medical imaging

Background:

• Accurate prediction of fetal growth abnormalities, specifically small for gestational age (SGA) and large for gestational age (LGA) fetuses, is crucial for optimizing perinatal outcomes.
• Current predictive models often rely on late-term assessments, potentially limiting timely interventions.

Purpose of the Study:

• To evaluate the efficacy of maternal and fetal parameters obtained during second and third trimester ultrasounds for predicting SGA and LGA.
• To compare the predictive performance of second trimester, third trimester, and combined ultrasound models.

Main Methods:

• A retrospective cohort study involving 1979 singleton pregnancies.
• Utilized routine second (20–24 weeks) and third (30–34 weeks) trimester ultrasound data, including estimated fetal weight (EFW) and Doppler indices (uterine arteries PI, umbilical PI).
• Excluded cases of SGA delivered before 30 gestational weeks.

Main Results:

• Second trimester ultrasound parameters (EFW2, uterine arteries PI, maternal characteristics) showed predictive value for SGA (AUC=0.815) and LGA (AUC=0.793).
• Incorporating third trimester data (EFW3, EFW2, uterine arteries PI2, umbilical PI, maternal characteristics) substantially improved prediction for SGA (AUC=0.896) and LGA (AUC=0.882).
• Contingent screening using a second trimester risk stratification model demonstrated comparable effectiveness to combined models for both SGA (AUC=0.882) and LGA (AUC=0.861).

Conclusions:

• A predictive model utilizing second trimester ultrasound parameters effectively identifies fetuses at risk for SGA and LGA.
• The addition of third trimester ultrasound data significantly enhances the accuracy of SGA and LGA prediction.
• Contingent screening offers a feasible and effective approach for risk stratification in fetal growth assessment.