Gastroschisis: incidence and prediction of growth restriction.

Abstract

Fetuses with gastroschisis are at increased risk of intrauterine growth restriction (IUGR). However, there is a tendency for underestimation of fetal abdominal circumference and hence fetal weight, leading to overdiagnosis of IUGR. Our objective was to evaluate the accuracy of ultrasound for the prediction of being small for gestational age (SGA) at birth in these cases. A retrospective study of prenatally diagnosed cases of gastroschisis was conducted at a tertiary center. Fetal weight was estimated using the formula of Hadlock. IUGR was defined as an estimated fetal weight ≤10th percentile for gestational age. SGA at the time of birth was defined as a birth weight ≤10th percentile for gestational age. The incidence of IUGR on last ultrasound and that of SGA at birth were calculated, and the precision of ultrasound in predicting SGA was determined. IUGR was reported on the last ultrasound prior to delivery in 9/25 cases (36%). Postnatally, 13/25 newborns (52%) were SGA. All sonographically suspected cases of IUGR based on the last ultrasound were SGA at birth. The positive predictive value of the last ultrasound in identifying SGA was 100%. At least half of the infants affected by gastroschisis were SGA at birth. Sonographic estimation of fetal weight within 1 month of birth reliably predicted SGA in infants with gastroschisis.