Mortality in prenatally detected congenital small bowel obstructions: systematic review and meta-analysis

To assess the risk of intrauterine fetal demise (IUFD) and postnatal death, and timing of demise in fetuses with a small bowel obstruction, in relation to isolated and nonisolated anomalies.

Embase (Ovid), MEDLINE (Ovid), and Cochrane Library were searched from inception to November 27, 2025.

We excluded studies before the year 2000 to reduce the possible impact of improved prenatal and neonatal care on the outcome measures. Cohort studies and case series of >10 cases reporting on outcome (stillbirths and (post)neonatal death) of prenatally detected small bowel obstructions were included. Studies, including various types of gastrointestinal obstructions and both pre- and postnatally detected cases, were eligible if prenatally suspected congenital small bowel obstruction cases could be analyzed separately. No language restriction was applied. Cases solely reporting on the outcome on liveborn cases, animal studies, and conference abstracts were excluded.

The primary outcome was IUFD. The secondary outcome was postnatal death. Data on associated structural and chromosomal anomalies were collected to evaluate the occurrence of mortality in isolated and nonisolated cases. Meta-analysis was performed to calculate the pooled proportions of IUFD and postnatal death, with separate analyses conducted for duodenal and jejunoileal obstructions.

The systematic review included 20 studies of 774 fetuses with small bowel obstruction. The pooled risk of IUFD was 6.4% [95% CI, 4.6%-8.9%]. Among IUFD cases with available information on additional anomalies, 43.8% (14/32) were classified as isolated. Median gestational age at IUFD was 33+3 weeks, IQR 32+4-34+2 weeks. Duodenal obstruction was associated with a pooled IUFD risk of 6.1% [95% CI 3.6%-10.0%] and jejunoileal obstruction with a pooled IUFD risk of 5.3% [95% CI, 2.6%-10.6%]. In addition, the pooled postnatal death risk was 8.5% [95% CI, 5.0%-14.2%], the majority of which occurred in nonisolated cases. The pooled postnatal death risk for suspected duodenal obstructions was 11.2% [95% CI, 6.3%-19.2%] and 3.9% [95% CI, 1.4%-10.4%] for jejunoileal obstructions.

Our findings suggest that the risk of IUFD in fetuses with small bowel obstruction might not solely be attributable to additional structural or chromosomal anomalies. While evidence supporting the benefits of daily fetal monitoring on outcomes remains limited, monitoring from 32 to 33 weeks of gestation may be appropriate given the substantial risk of IUFD. Counseling should address both the absolute risks and the uncertain impact of monitoring. To mitigate the risk of term IUFD, induction of labor from 37 weeks could be considered while reducing the risks associated with premature delivery.