Outcomes of both complex and isolated cases of infants with large stomach on fetal ultrasound

Background: A sonographically large fetal stomach has been associated with gastrointestinal obstruction, per case reports, and is often followed up with serial ultrasound examinations. The frequency of this phenomenon has not been systematically studied, resulting in challenges in counseling parents about the prognosis and making cost-benefit analysis of serial ultrasound follow-up difficult to assess. Objective: This study aimed to determine the frequency at which an enlarged fetal stomach as the sole abnormality on fetal ultrasound reflects a bowel obstruction to aid in parental counseling and determine the best practice for follow-up. Study Design: We performed a retrospective cohort study of all prenatal sonographic cases in which a large fetal stomach was visualized between January 1, 2002, and June 1, 2016. The inclusion criteria required a fetal diagnosis of a large stomach, defined as an increased measurement in ≥2 dimensions based on a nomogram, that resulted in a liveborn delivery within the Johns Hopkins Health System. We excluded pregnancy loss, pregnancy termination, and cases delivered outside of the Johns Hopkins Health System. Cases were subclassified as isolated or complex based on the absence or presence of additional ultrasound findings at initial presentation of the enlarged stomach. The perinatal outcomes and maternal demographics were determined and compared between isolated and complex cases. Results: Of 57,346 total cases with ultrasound examinations in the Johns Hopkins Health System within the study time frame, 348 fetuses had enlarged stomachs, with 241 (69.3%) who met the inclusion criteria as follows: 161 (66.8%) isolated and 80 (33.2%) complex. Of the 161 isolated cases, 1 resulted in neonatal small bowel obstruction (0.62%). Of note, 158 of the isolated large stomach cases (98.1%) had no postnatal abnormalities of any kind. Of the 80 complex cases, 18 (22.5%) resulted in neonatal gastrointestinal obstruction (14 cases of duodenal atresia and 4 cases of jejunal atresia). Those with isolated findings were significantly less likely to deliver preterm (n=24 [14.9%] vs n=35 [43.8%]; P<.001), be complicated by polyhydramnios (n=18 [11.2%] vs n=23 [28.8%]; P<.001), have a neonatal intensive care unit admission (n=31 [19.3%] vs n=76 [95.0%]; P<.01), or have a major surgical procedure (n=2 [1.2%] vs n=66 [82.5]; P<.001) compared with complex cases. Conclusion: We found that 0.62% of isolated large fetal stomachs (1 of 161) were associated with neonatal intestinal obstruction. Of the complex cases with an enlarged stomach, 18 of 80 (22.5%) were found to have a gastrointestinal obstruction; by definition, none of these complex cases began as an isolated large stomach as their initial ultrasound finding, but rather had other concurrent sonographic abnormalities, including a double bubble sign and intestinal dilation. With a prevalence of <1% resulting in the development of a small bowel obstruction, our results suggest that, when isolated, a large stomach does not seem to warrant serial prenatal ultrasound follow-up or postnatal imaging and is likely to reflect an incidental finding.