Accuracy of Ultrasound to Predict Neonatal Birth Weight Among Fetuses With Gastroschisis: Impact on Timing of Delivery

Interval growth across gestation in pregnancies with fetal gastroschisis

BACKGROUND

Gastroschisis is often complicated by fetal growth restriction, preterm delivery, and prolonged neonatal hospitalization. Prenatal management and delivery decisions are often based on estimated fetal weight and interval growth; however, appropriate interval growth from week to week across gestation for these fetuses is poorly understood.

OBJECTIVE

This study aimed to determine the median increase in overall estimated fetal weight and individual biometric measurements across each week of gestation in pregnancies with fetal gastroschisis and to assess whether lower in utero fetal weight gain is predictive of postnatal growth or adverse neonatal outcomes.

STUDY DESIGN

This was a retrospective cohort study of pregnancies with gastroschisis evaluated at 5 institutions of the University of California Fetal-Maternal Consortium from December 2014 to December 2019. The inclusion criteria were prenatally diagnosed gastroschisis with at least 1 ultrasound performed at a University of California Fetal-Maternal Consortium institution. Estimated fetal weight and individual biometric measurements were recorded for each ultrasound performed at a University of California Fetal-Maternal Consortium institution from the time of gastroschisis diagnosis to delivery. Median estimated fetal weight and biometric measurements were calculated for each gestational age in 1-week increments. Neonatal outcomes collected were birthweight, length of stay, complications of gastroschisis (bowel atresia, bowel stricture, ischemic bowel before closure, or severe pulmonary hypoplasia), and growth failure at discharge.

RESULTS

We identified 95 pregnancies with fetal gastroschisis who, in aggregate, had 360 growth ultrasounds at a University of California Fetal-Maternal Consortium institution. The median interval growth was 130 g/wk. The median estimated fetal weight and abdominal circumference in fetal gastroschisis cases were approximately the tenth percentile on the Hadlock growth curve across gestation. Moreover, the median biparietal diameter, head circumference, and femur length measurements remained below the 50th percentile on the Hadlock growth curve across gestation. The median birthweight for neonates with less than the median weekly prenatal weight gain was less than for those with greater than the median weekly prenatal weight gain (2185 g vs 2780 g; P<.01). There was no difference in prenatal weight gain trajectory when comparing neonates who had or did not have bowel complications of gastroschisis.

CONCLUSION

In this multicenter cohort of pregnancies with fetal gastroschisis, the median interval growth was 130 g/wk, and overall, in utero growth closely followed the tenth percentile on the Hadlock curve. Poor prenatal growth in cases of fetal gastroschisis correlates with lower neonatal weights but did not predict a more complicated course.

Gastroschisis: A State-of-the-Art Review

Gastroschisis, the most common type of abdominal wall defect, has seen a steady increase in its prevalence over the past several decades. It is identified, both prenatally and postnatally, by the location of the defect, most often to the right of a normally-inserted umbilical cord. It disproportionately affects young mothers, and appears to be associated with environmental factors. However, the contribution of genetic factors to the overall risk remains unknown. While approximately 10% of infants with gastroschisis have intestinal atresia, extraintestinal anomalies are rare. Prenatal ultrasound scans are useful for early diagnosis and identification of features that predict a high likelihood of associated bowel atresia. The timing and mode of delivery for mothers with fetuses with gastroschisis have been somewhat controversial, but there is no convincing evidence to support routine preterm delivery or elective cesarean section in the absence of obstetric indications. Postnatal surgical management is dictated by the condition of the bowel and the abdominal domain. The surgical options include either primary reduction and closure or staged reduction with placement of a silo followed by delayed closure. The overall prognosis for infants with gastroschisis, in terms of both survival as well as long-term outcomes, is excellent. However, the management and outcomes of a subset of infants with complex gastroschisis, especially those who develop short bowel syndrome (SBS), remains challenging. Future research should be directed towards identification of epidemiological factors contributing to its rising incidence, improvement in the management of SBS, and obstetric/fetal interventions to minimize intestinal damage.