Predicting birth weight in fetuses with gastroschisis

Estimating fetal weight in gastroschisis: A 10 year audit of outcomes at the National Maternity Hospital

OBJECTIVE

To identify whether conventional methods of estimating fetal growth (Hadlock's formula), which relies heavily on abdominal circumference measurements, are accurate in fetuses with gastroschisis.

METHODS

A retrospective cohort study was performed between the period January 1, 2011 and December 31, 2021 in a tertiary referral maternity hospital identifying all pregnancies with a diagnosis of gastroschisis. Projected fetal weight was obtained using the formula (EFW [Hadlock's formula] + 185 g × [X/7]) where X was the number of days to delivery.

RESULTS

During the study period 41 cases were identified. The median maternal age was 25. The median BMI was 25 and 63% were primiparous women (n = 26). Median gestation at diagnosis was 21 weeks. Median gestation at delivery was 36 weeks. A total of 4.8% of mothers had a history of drug use (n = 2). The rate of maternal tobacco use was 21.9% (n = 9). A total of 4.8% of fetuses had additional congenital anomalies including amniotic band syndrome and myelomeningocele (n = 2). Estimated fetal weight (EFW) and birth weight data were available for 34 cases. A Wilcoxon signed-rank test showed projected EFW using Hadlock's formula did not result in a statistically significant different birth weight (Z = -1.3, P = 0.169). Median projected weight and actual birth weight were 2241.35 and 2415 g respectively. Median difference was 0.64 g (95% CI: -148 to -28.5).

CONCLUSION

Our data showed accuracy using standard formulae for EFW in fetuses with gastroschisis.

Comparison of Perinatal Outcomes between Patients with Suspected Complex and Simple Gastroschisis

OBJECTIVE

 The aim of this study was to compare perinatal outcomes between patients with and without prenatal ultrasound markers predictive of complex gastroschisis.

STUDY DESIGN

 A prospective cohort of 98 patients with isolated fetal gastroschisis underwent antenatal ultrasound and delivered in a tertiary referral center. Patients were classified according to eight ultrasonographic markers predictive of complexity, and perinatal outcomes were assessed accordingly. The primary outcome was the presence of fetal growth restriction and staged SILO reduction postnatally. RESULTS:  Of all fetuses, 54.1% (n = 53) displayed ultrasonographic markers predictive of complexity at 32.7 ± 4.3 weeks of gestation. Gastric dilatation was the most frequent marker followed by extra-abdominal bowel dilatation. The presence of ultrasound markers predictive of complexity, was not associated with fetal growth restriction but its absence was less associated with staged SILO reduction of the abdominal wall postnatally with a relative risk of 0.79 (CI 95% 0.17-0.53).

CONCLUSION

 Fetuses with ultrasound markers that predict complexity were not associated with fetal growth restriction, but its absence was less associated with staged SILO reduction of the abdominal wall postnatally. It is necessary to unify criteria, establish cut-off points, and the optimal moment to measure these markers.

KEY POINTS

· The association between ultrasound markers and adverse perinatal outcomes in fetuses with gastroschisis remain controversial.. · The absence of ultrasound markers that predict complexity was less associated with staged SILO reduction postnatally.. · It is necessary to unify criteria, establish cut-off points, and the optimal moment to measure these markers..

Optimal timing of delivery for growth restricted fetuses with gastroschisis: A decision analysis

OBJECTIVE

Our objective was to determine the optimal timing of delivery of growth restricted fetuses with gastroschisis in the setting of normal umbilical artery (UA) Dopplers.

METHODS

We designed a decision analytic model using TreeAge software for a hypothetical cohort of 2000 fetuses with isolated gastroschisis, fetal growth restriction (FGR), and normal UA Dopplers across 34-39 weeks of gestation. This model accounted for costs and quality adjusted life years (QALYs) for the pregnant individual and the neonate. Model outcomes included stillbirth, respiratory distress syndrome (RDS), necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH), short gut syndrome (SGS), neonatal sepsis, neonatal death, and neurodevelopmental disability (NDD).

RESULTS

We found 38 weeks to be the optimal timing of delivery for minimizing overall perinatal mortality and leading to the highest total QALYs. Compared to 37 weeks, delivery at 38 weeks resulted in 367.98 more QALYs, 2.22 more cases of stillbirth, 2.41 fewer cases of RDS, 0.02 fewer cases of NEC, 1.65 fewer cases of IVH, 0.5 fewer cases of SGS, 2.04 fewer cases of sepsis, 11.8 fewer neonatal deaths and 3.37 fewer cases of NDD. However, 39 weeks were the most cost-effective strategy with a savings of $1,053,471 compared to 38 weeks. Monte Carlo analysis demonstrated that 38 weeks was the optimal gestational age for delivery 51.70% of the time, 39 weeks were optimal 47.40% of the time, and 37 weeks was optimal 0.90% of the time.

CONCLUSION

Taking into consideration a range of adverse perinatal outcomes and cost effectiveness, 38-39 weeks gestation is ideal for the delivery of fetuses with gastroschisis, FGR, and normal UA Dopplers. However, there are unique details to consider for each case, and the timing of delivery should be individualized using shared multidisciplinary decision making.

Correlation between estimated fetal weight and weight at birth in infants with gastroschisis and omphalocele

BACKGROUND

An accurate estimated fetal weight (EFW) calculated with traditional formulae in cases of abdominal wall defects (AWDs) can be challenging. As a result of reduced abdominal circumference, fetal weight may be underestimated, which could affect prenatal management. Siemer et al. proposed a formula without the use of abdominal circumference, but it is not used in our protocols yet.

OBJECTIVES

Our aim was to evaluate the correlation of EFW and birth weight in fetuses with AWD by using Hadlock 1, Hadlock 2, and Siemer et al.'s formulae. Our secondary goal was to evaluate how often fetuses classified as small for gestational age (SGA) were in fact SGA at birth.

STUDY DESIGN

This was a retrospective cohort study of gestations complicated by gastroschisis and omphalocele at two tertiary-care centers in Brazil and Italy during an 8-year period. Of a total of 114 cases, 85 (44 cases of gastroschisis and 41 cases of omphalocele) met our criteria.

RESULTS

The last prenatal scan was performed 5.2 (±4.1) days before birth. The mean gestational age at birth was 37.2 (±1.8) weeks. Correlation of EFW with birth weight was calculated with the three formulae with and without adjustment for weight gain between scan and birth, with the use of the Spearman coefficient. The correlation between EFW and weight at birth was positive according to all three formulae for the infants with gastroschisis. This finding was not confirmed in the infants with omphalocele. All formulae overestimated the number of SGA cases: although only 17.6% of fetuses were actually SGA at birth, the Hadlock formulae had classified nearly 35% of them as SGA, and Siemer et al.'s formula, 15.3%.

CONCLUSION

All three formulae yielded a good correlation between EFW in the last scan and birth weight in the infants with gastroschisis but not for those with omphalocele. Cases of SGA were overestimated.

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

OBJECTIVES

To determine the accuracy of ultrasound estimation of fetal weight among fetuses with gastroschisis and how the diagnosis of fetal growth restriction (FGR) affects the timing of delivery.

METHODS

This was a retrospective cohort study including all fetuses with a diagnosis of gastroschisis at our institution from November 2012 through October 2017. We excluded multiple gestations, pregnancies with major structural or chromosomal abnormalities, and those for which prenatal and postnatal follow-up were unavailable. Performance characteristics of ultrasound to predict being small for gestational age (SGA) were calculated for the first and last ultrasound estimations of fetal weight.

RESULTS

Our cohort included 75 cases of gastroschisis. At the initial ultrasound estimation, 15 of 58 (25.9%) fetuses met criteria for FGR; 48 of 70 (68.6%) met criteria at the time of the last ultrasound estimation (median, 34.7 weeks). Cesarean delivery was performed for 37 of 75 (49.3%), with FGR and concern for fetal distress as the indication for delivery in 17 of 37 (45.9%). Only 6 of 17 (35.3%) of the neonates born by cesarean delivery for an indication of FGR and fetal distress were SGA. The initial ultrasound designation of FGR corresponded to SGA at birth in 8 of 15 (53.3%), whereas the last ultrasound estimation corresponded to SGA in 17 of 48 (35.4%). The initial ultrasound estimation agreed with the last ultrasound estimation before delivery with the diagnosis of FGR in 13 of 15 (86.7%).

CONCLUSIONS

Ultrasound in the third trimester was sensitive but had a low positive predictive value and low accuracy for the diagnosis of SGA at birth for fetuses with gastroschisis. A large proportion of fetuses were born by cesarean delivery with indications related to FGR or fetal concerns.

Individualized growth assessment in pregnancies complicated by fetal gastroschisis

OBJECTIVE

Prenatal ultrasound (US) has been shown to overestimate the incidence of suspected fetal growth restriction (FGR) in gastroschisis cases. This is largely because of altered sonographic abdominal circumference (AC) measurements when comparing gastroschisis cases with population nomograms. Individualized Growth Assessment (IGA) evaluates fetal growth using serial US measurements that allow consideration of the growth potential for a given case. Our goal was to assess the utility of IGA for distinguishing normal and pathological fetal growth in gastroschisis cases.

STUDY DESIGN

Pregnancies with prenatally diagnosed fetal gastroschisis were managed and delivered at a single academic medical center. US fetal biometry including head circumference (HC), abdominal circumference (AC), and femur diaphysis length (FDL), and neonatal measurements including birthweight and HC were collected and analyzed for 32 consecutive fetal gastroschisis cases with at least two 2nd and two 3rd trimester measurements. Second trimester growth velocities were compared to a group of 118 non-anomalous fetuses with normal neonatal growth outcomes. Gastroschisis cases were classified into groups based on fetal growth pathology score (FGPS9) patterns. Agreement between IGA (FGPS9) and serial conventional estimated fetal weight (EFW) measurements for determining growth pathology was evaluated. Neonatal size outcomes were compared between conventional birthweight classifications for determining small for gestational age (SGA) and IGA Growth Potential Realization Index (GPRI) for weight and head circumference measurements.

RESULTS

Fetal growth pathology score (FGPS9) measurements identified three in-utero growth patterns: no growth pathology, growth restriction and recovery, and progressive growth restriction. In the no growth pathology group (n = 19), there was 84% agreement between IGA and conventional methods in determining pathological growth in both the 3rd trimester and at birth. In the growth restriction and recovery group (n = 7), there was 71% agreement both in the 3rd trimester and at birth between IGA and conventional methods. In the progressive growth restriction group (n = 5), there was 100% agreement in the 3rd trimester and 60% agreement at birth between IGA and conventional methods.

CONCLUSION

We present the first study using IGA to evaluate normal and pathological fetal growth in prenatally diagnosed gastroschisis cases. IGA was able to delineate two 3rd trimester growth pathology patterns - one with persistent growth restriction and another with in-utero growth recovery. Further validation of these initial findings with larger cohorts is warranted.

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.

Accuracy of estimated fetal weight assessment in fetuses with abdominal wall defects

BACKGROUND

Gastroschisis and omphalocele are congenital abdominal wall defects in which the bowel and other abdominal contents extrude from the fetal abdominal cavity. Standard formulas for estimated fetal weight using ultrasound include fetal abdominal circumference measurement and have a range of error of approximately 10%. It is unknown whether the accuracy of estimated fetal weight assessment is compromised in fetuses with abdominal wall defects because of the extrusion of abdominal contents.

OBJECTIVE

This study aimed to assess the accuracy of standard estimated fetal weight assessment in fetuses with abdominal wall defects by comparing prenatal assessment of fetal weight with actual birthweight.

STUDY DESIGN

A retrospective cohort study of fetuses diagnosed with gastroschisis or omphalocele was performed at a single center from 2012 to 2018. Fetuses with additional anomalies or confirmed chromosome abnormalities were excluded. Estimated fetal weight was calculated using the Hadlock formula. Published estimates of fetal growth rate were used to establish a projected estimated fetal weight at birth from the final growth ultrasound, and the percent difference between projected estimated fetal weight at birth and actual birthweight was calculated. The Wilcoxon rank-sum test was used to examine the difference between projected estimated fetal weight and actual birthweight.

RESULTS

We had complete data for 112 fetuses with abdominal wall defects, including 85 with gastroschisis and 27 with omphalocele. The median (interquartile range) projected estimated fetal weight was similar to median birthweight, at 2283 g (interquartile range, 2000-2810) and 2306 g (interquartile range, 1991-264), respectively, which did not represent a statistically significant difference between projected estimated fetal weight and actual birthweight (P=.32). The median percent error was 6.8 (3.1-12.8). In addition, we did not find any statistical difference between projected estimated fetal weight and actual birthweight in patients with gastroschisis (P=.52) or omphalocele (P=.35) individually. Estimated fetal weight was underestimated in most cases (n=68 [60.7%]).

CONCLUSION

In fetuses with abdominal wall defects, standard measurement of fetal weight shows an accuracy that is at least comparable with previously established margins of error for ultrasound assessment of fetal weight. Standard estimated fetal weight assessment remains an appropriate method of estimating fetal weight in these fetuses.

Is there a role for fetal interventions in gastroschisis management? - An updated comprehensive review

We conducted a comprehensive evidence-based review on the epidemiology and current standard of care of gastroschisis management as well as the pathophysiology, rationale and feasibility of fetal therapy as a viable alternative. Gastroschisis is a periumbilical abdominal wall defect characterized by abdominal viscera herniation in utero. It affects 4 in 10 000 live births, but the prevalence has steadily increased in recent years. Gastroschisis is typically diagnosed on routine second-trimester ultrasound. The overall prognosis is favorable, but complex gastroschisis, which accounts for about 10% to 15% of cases, is associated with a higher mortality, significant disease burden and higher healthcare costs due to long- and short-term complications. The current standard of care has yet to be established but generally involves continued fetal surveillance and multidisciplinary perinatal care. Postnatal surgical repair is achieved with primary closure, staged silo closure or sutureless repair. Experimental animal studies have demonstrated the feasibility of in utero closure, antiinflammatory therapy and prenatal regenerative therapy. However, reports of early preterm delivery and amnioinfusion trials have failed to show any benefit in humans. Further experimental studies and human trials are necessary to demonstrate the potential benefit of fetal therapy in gastroschisis.

Accuracy of sonographic estimation of weight in fetuses with abdominal wall defects

BACKGROUND

Accurate estimation of fetal weight is essential in guiding management of fetuses with abdominal wall defects (AWDs), as growth restriction is an important predictor of perinatal morbidity and mortality. Several sonographic formulae are available involving multiple biometric parameters, but abdominal circumference measurements may underestimate weight in fetuses with AWDs. No formula has yet shown superior accuracy.

AIMS

The objectives of this study were to evaluate, in fetuses with gastroschisis and omphalocoele, the accuracy of a sonographic estimated fetal weight (EFW) formula proposed by Siemer and colleagues, specifically for use in fetuses with AWDs compared to the commonly used Hadlock IV formula in estimating fetal weight, and detecting small for gestational age (SGA) fetuses.

MATERIALS AND METHODS

A retrospective cohort of 113 fetuses with AWDs was identified from an Australian teaching hospital over 13 years. Pregnancy data and sonographic fetal biometry parameters were obtained. The accuracy of each formula in predicting birthweight was compared using Bland-Altman limits of agreement, and the intraclass correlation coefficient between EFW and actual birthweight. Performance of each formula in detecting SGA fetuses was determined.

RESULTS

The Siemer and Hadlock formulae have similar accuracies for predicting birthweight in fetuses with AWDs. The Hadlock formula has a higher detection rate for SGA < 10^th centile and < 3^rd centile compared to the Seimer formula (84% vs 68% and 83% vs 67% respectively), albeit with a higher false-positive rate.

CONCLUSION

There is no clear clinical advantage in using the Siemer formula, which is specifically designed for fetuses with AWDs, over the Hadlock formula to estimate weight in fetuses with AWDs.

Advances in prenatal and perinatal diagnosis and management of gastroschisis

Gastroschisis is a congenital, ventral wall defect associated with bowel evisceration. The defect is usually to the right of the umbilical cord insertion and requires postnatal surgical correction. The fetus is at risk for complications such as intrauterine growth restriction, preterm delivery, and intrauterine fetal demise. In addition, complex cases, defined by the presence of intestinal complications such as bowel atresia, stenosis, perforation, or ischemia, occur in up to one third of pregnancies affected by gastroschisis. As complex gastroschisis is associated with increased morbidity and mortality, research has focused on the prenatal detection of this high risk subset of cases. The purpose of this review is to discuss the prenatal, diagnostic approach to the identification of gastroschisis, to describe potential signs of complex gastroschisis on prenatal ultrasound, to review current guidelines for antepartum management and delivery planning, and to summarize results of both past and current intervention trials in fetuses with gastroschisis.