Objective
The purpose of this study was to determine whether prenatal intraabdominal bowel dilation (IBD) is associated with increased postnatal complications in fetuses with gastroschisis.
Study Design
A retrospective review was performed on all maternal-fetus pairs with prenatally diagnosed gastroschisis that was treated at the University of California San Francisco from 2002-2008. Postnatal outcomes were compared between fetuses with and without IBD.
Results
Forty-three of 61 maternal-fetal pairs met the criteria for inclusion. Sixteen fetuses (37%) had evidence of IBD. Fetuses with IBD were significantly more likely to have postnatal bowel complications (38% vs 7%; P = .037). The presence of multiple loops of IBD (n = 6) as opposed to a single loop (n = 10) was associated highly with bowel complications and increased time to full enteral feeding and length of hospital stay (100% vs 0% [ P = .001]; 44 vs 23 days [ P = .034]; 69 vs 27 days [ P = .001], respectively).
Conclusion
IBD is associated with increased postnatal complications in infants with prenatally diagnosed gastroschisis; however, this association seems to be limited to those with multiple loops of dilated intraabdominal bowel.
Gastroschisis is a congenital anomaly that is characterized by the herniation of fetal intestine through a full-thickness defect in the abdominal wall. The incidence of gastroschisis ranges from 0.5-1 per 10,000 births. Prenatal detection of gastroschisis is facilitated by the combination of maternal serum alpha fetoprotein measurement and widespread use of routine prenatal ultrasound. The apparent increase in incidence of prenatally detected gastroschisis over the past 2 decades has been attributed to these advancements in screening and detection. Although the overall survival rate for neonates with gastroschisis is very good (range, 90–97% ) both morbidity and mortality rates are highly correlated with the degree of bowel disease at birth. Gastrointestinal complications such as perforation or atresia occur in 10-20% of cases. Presence of gastrointestinal complications is associated with mortality rates as high as 28%, longer hospitalization, and prolonged parenteral nutrition with its accompanying risks of infection, growth restriction, metabolic disturbances, and severe liver disease. Identification of prenatal prognostic factors would help identify which patients would benefit from intensive fetal surveillance and potentially early intervention or delivery and more informed parental counseling.
Identification of discriminating prenatal indicators of outcome has not been very successful. Dilation of extraabdominal bowel loops has been studied but has not been proved to be a useful predictor of postnatal outcome. The differences in definition of dilation and small sample sizes of previous studies limit the consensus on which measurements are consistently predictive of poor outcome. Furthermore, externalized bowel seems to dilate as “normal” phenomenon in many gastroschisis fetuses in the third trimester who do very well after birth ( Figure 1 ). The development of intraabdominal bowel dilation (IBD) in these fetuses is much less common, with an estimated report in the limited published literature on this topic that ranges from 8-17%. In a recent study, Nick et al suggested that the presence of IBD in fetuses with gastroschisis may have important prognostic value. The purpose of this study was to evaluate whether IBD in fetuses with gastroschisis is associated with increased postnatal complications.
Methods
A retrospective review was conducted on all cases of gastroschisis who were delivered at our institution, the University of California San Francisco (UCSF), between May 2002 and June 2008. The study population included those maternal-fetus pairs with a prenatal diagnosis of gastroschisis, with at least 1 prenatal ultrasound examination performed at the UCSF Medical Center and delivery at or transported to UCSF as newborn infants for postnatal care. Pregnancies that were complicated by terminations of pregnancy were excluded. Maternal-fetus pairs were also excluded if medical records were incomplete or unavailable. Approval for this study was obtained from the institutional review board at the UCSF Medical Center.
All digital images of the prenatal ultrasound studies were reviewed retrospectively by the senior author (R.B.G.) for the following findings: fetal growth parameters, amniotic fluid volume, abdominal wall defect size, and the presence and degree of IBD. If a dilated intraabdominal loop of bowel was identified, the diameter of the loop was measured with electronic calipers from inner wall to inner wall at the region of maximal observed dilation. If IBD was not noted, there was no measurement because IBD was defined as a clinical diagnosis that then can be measured subsequently. As for the comparison of the degree of IBD among the fetuses, an average diameter was calculated for each trimester in cases in which >1 ultrasound showed IBD. Presence of abnormally dilated extraabdominal bowel loops that was determined by the qualitative descriptions reported by 2 independent sonologists was also recorded. However, exteriorized loops were not remeasured.
Maternal charts were reviewed for maternal age and parity, gestational age at evaluation, prenatal care, and the presence of other fetal abnormalities. In addition, the estimated gestational age at the time of delivery, birthweight, the indication for delivery, and the type of delivery were recorded. Postnatal charts were reviewed for method of abdominal wall closure, time to complete abdominal wall defect closure, time to initial and full enteral feeding, frequency of bowel-related and nonbowel complications, number of days on ventilation, and length of hospital stay. The following bowel complications were considered severe: atresia, perforation, obstruction, necrosis, and volvulus with and without death.
Differences between fetal groups with and without IBD were determined by use of the Fisher’s exact test or the Student t test, when appropriate. Data are presented as the average ± SD. Probability values were 2-tailed and considered statistically significant if < .05.
Results
A total of 61 maternal-fetus pairs were identified with prenatal gastroschisis and evaluated at our center. Forty-three maternal-fetus pairs met the criteria for inclusion in our study. Eighteen maternal-fetus pairs were excluded for the following reasons: incomplete data such as no maternal identification information (n = 14), termination of pregnancy (n = 2), and not yet delivered (n = 2). The mean maternal age was 23.3 ± 4.7 years. Patients had an average of 3 scans at our institution during their pregnancy; 77% of the patients had at least 1 second- and third-trimester ultrasound available for review. Eight fetuses (19%) were born by cesarean delivery, with indications in 6 cases because of nonreassuring fetal heart tracing, concerning change in bowel status or both; in 1 case because of breech presentation, and in 1 case because of a planned repeat cesarean delivery. Three of the 43 newborns had been born at an outside facility and transferred to our hospital. Forty newborns (93%) underwent staged reduction with a silo, and 3 newborns had primary closure of the abdominal wall defect.
Overall, 27 newborns (63%) demonstrated morbidity; the most common bowel complication was atresia, and nonbowel complication was sepsis. Four newborns (9%) had an atresia, 1 of whom also had an intestinal perforation and another who had midgut volvulus, bowel necrosis, and perforation. One patient (2%) had isolated bowel necrosis with associated short gut syndrome and was total parenteral nutrition (TPN)-dependent at time of discharge. Four of the 5 newborn infants with severe bowel-related complications required bowel resection (2 on the first day of life, and the other 2 at approximately 1 month of age).
Of the 43 maternal-fetus pairs, 16 fetuses (37%) had some degree of IBD on prenatal ultrasound. These fetuses were delivered earlier, compared with those fetuses without IBD (34.2 ± 2.26 wks vs 36 ± 1.75 wks, respectively; P = .006). This difference in delivery timing may be due to the more aggressive delivery and treatment for these fetuses who were diagnosed with IBD at our institution. There were no statistically significant differences in maternal age, birthweight, incidence of polyhydramnios, size of abdominal wall defect, or delivery mode between the fetuses with and without IBD.
The postnatal outcomes of fetuses with and without IBD are summarized in Table 1 . Fetuses with IBD were significantly more likely to have bowel-related complications vs those fetuses without IBD (38% vs 7%; P = .037). The death rates were similar and low for both the IBD and non-IBD groups: 1 neonatal death (fetus with IBD) was due to bowel-related complications, and 1 neonatal death (fetus had no IBD) was due to significant liver injury that resulted in coagulopathy and multisystem organ failure. There were no statistically significant differences in estimated gestational age at diagnosis of IBD or interval from detection of dilation to delivery between the fetuses with and without bowel complications.
| Characteristic | All (n = 43) | No IBD (n = 27) | Any IBD (n = 16) | P value a |
|---|---|---|---|---|
| Maternal age, y | 23.3 ± 4.7 | 23.2 ± 4.9 | 23.4 ± 4.5 | .92 |
| Vaginal delivery, n (%) | 35 (81) | 23 (85) | 11 (69) | .26 |
| Delivery indication | 6 (14) | 8 (30) | 11 (69) | .025 |
| EGA at delivery, wk | 35.4 ± 2.2 | 36 ± 1.8 | 34.2 ± 2.3 | .006 |
| Birthweight, g | 2433 ± 542 | 2514 ± 557 | 2298 ± 505 | .21 |
| Defect closure, d | 4.3 ± 3.7 | 3.9 ± 2.6 | 4.6 ± 5.3 | .56 |
| Time on ventilator, d | 7 ± 4.6 | 7.6 ± 5.3 | 5.9 ± 3.1 | .26 |
| Days to initial enteral feeding | 15.8 ± 8.2 | 16.8 ± 9.1 | 14.1 ± 6.6 | .33 |
| Days to full enteral feeding | 29.8 ± 18.3 | 30 ± 19 | 29.6 ± 17.7 | .95 |
| Length of hospitalization, d | 36.8 ± 23.2 | 34.4 ± 20.3 | 40.9 ± 27.8 | .39 |
| Neonatal death | 2 (5%) | 1 (4%) | 1 (6%) | 1.00 |
| Bowel complications | 8 (19%) | 2 (7%) | 6 (38%) | .037 |
| Bowel resections | 4 (2%) | 1 (4%) | 3 (19%) | .14 |
| EGA at diagnosis of IBD, wk | — | — | 29 ± 5.13 | — |
| IBD diameter, mm | — | — | 17.8 ± 6.29 | — |
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