Gastroschisis: epidemiology and mode of delivery, 2005–2013




Background


Gastroschisis is a severe congenital anomaly the etiology of which is unknown. Research evidence supports attempted vaginal delivery for pregnancies complicated by gastroschisis in the absence of obstetric indications for cesarean delivery.


Objective


The objectives of the study evaluating pregnancies complicated by gastroschisis were to determine the proportion of women undergoing planned cesarean vs attempted vaginal delivery and to provide up-to-date epidemiology on the risk factors associated with this anomaly.


Study Design


This population-based study of US natality records from 2005 through 2013 evaluated pregnancies complicated by gastroschisis. Women were classified based on whether they attempted vaginal delivery or underwent a planned cesarean (n = 24,836,777). Obstetrical, medical, and demographic characteristics were evaluated. Multivariable log-linear regression models were developed to determine the factors associated with the mode of delivery. Factors associated with the occurrence of the anomaly were also evaluated in log-linear models.


Results


Of 5985 pregnancies with gastroschisis, 63.5% (n = 3800) attempted vaginal delivery and 36.5% (n = 2185) underwent a planned cesarean delivery. The rate of attempted vaginal delivery increased from 59.7% in 2005 to 68.8% in 2013. Earlier gestational age and Hispanic ethnicity were associated with lower rates of attempted vaginal delivery. Factors associated with the occurrence of gastroschisis included young age, smoking, high educational attainment, and being married. Protective factors included chronic hypertension, black race, and obesity. The incidence of gastroschisis was 3.1 per 10,000 pregnancies and did not increase during the study period.


Conclusion


Attempted vaginal delivery is becoming increasingly prevalent for women with a pregnancy complicated by gastroschisis. Recommendations from the research literature findings may be diffusing into clinical practice. A significant proportion of women with this anomaly still deliver by planned cesarean, suggesting further reduction of surgical delivery for this anomaly is possible.


Gastroschisis is a severe congenital anomaly that involves a full-thickness defect of the abdominal wall through which intestines and other organs may herniate. The defect typically occurs on the right side of normal umbilical cord insertion, and in the majority of cases can be detected by midtrimester ultrasound. Although the risk factors for gastroschisis are well documented and include young maternal age, smoking, and infection, the etiology is unknown.


Hypotheses for the cause of gastroschisis include a failure of mesoderm formation in the body wall, rupture of amnion around the umbilical ring, and sequelae from involution of the right umbilical vein or disruption of the right vitelline artery. The defect requires major neonatal surgical intervention and is associated with significant health care costs, neonatal morbidity, and perinatal mortality.


Routine obstetric management of gastroschisis includes increased fetal surveillance, given the higher risk for associated adverse obstetrical outcomes including fetal growth restriction and stillbirth. Although optimal delivery timing is unclear, early-term delivery may be indicated to reduce the risk for bowel complications and perinatal death.


An intervention that has not been shown to be beneficial is cesarean delivery. Data from earlier reports and a metaanalysis demonstrated no benefit for cesarean delivery; these findings are similar to those from later studies. Given the increased maternal morbidity with cesarean delivery, and lack of neonatal benefit, planned cesarean delivery specifically for gastroschisis is not recommended.


Given the evidence that cesarean delivery be reserved for obstetric indications, this analysis had 2 objectives: (1) to assess trends in planned vaginal delivery for pregnancies complicated by gastroschisis and (2) to provide up-to-date epidemiological information on demographic, medical, and obstetric risk factors for this anomaly.


Materials and Methods


The primary outcome of this population-based analysis was to determine whether women with pregnancies complicated by gastroschisis underwent planned cesarean delivery or attempted vaginal birth. The study utilized US vital statistics data based on the 2003 revision of the live birth certificates, and the analysis was restricted to women who had live births from 2005 through 2013.


Compared with the 1989 version, the 2003 birth certificate revision contains more detailed obstetric, medical, and demographic data. The updated format was incorporated gradually on a statewide basis. States using the revised format numbered 12 in 2005, 21 in 2006, 23 in 2007, 28 in 2009 (66% of all births), 33 in 2010 (76% of all births), 36 in 2011 (83% of all births), 38 in 2012 (86% of all births), and 41 in 2013 (90% of all births). The number of births available in this format increases annually, given this uptake. Fetal demises were excluded because maternal data for these pregnancies are limited.


The data set is provided by the National Vital Statistics System, a joint effort of the National Center for Health Statistics and states to provide access to statistical information from birth certificates. Birth certificates are required to be completed for all births, and federal law mandates national collection and publication of birth statistics. Prior analyses have addressed the validity of these data. Because US vital statistics data are both publically available and deidentified, this analysis was exempt from institutional review board approval.


Patients with potential indications for planned cesarean delivery other than gastroschisis were excluded from the primary analysis. Exclusion criteria included the following: (1) noncephalic presentation, (2) multiple gestation, (3) prior cesarean delivery, and (4) eclampsia. Only women who delivered between 28 and 41 weeks’ gestation were included in the primary analysis. Births from 2004 were excluded, given that a relatively small proportion of national births are represented in the 2003-revised birth certificate for this year.


Women were considered to have undergone an attempted vaginal delivery if they met 1 of the following criteria: (1) they underwent labor induction or augmentation; (2) they had a successful spontaneous, forceps, or vaginal delivery; or (3) they had a cesarean delivery in the setting of prolonged labor and/or fetal intolerance of labor. Patients were classified as undergoing planned cesarean delivery if they had a cesarean delivery without induction or augmentation of labor or a diagnosis of fetal intolerance or prolonged labor.


Demographic, obstetrical, and medical factors possibly associated with attempted mode of delivery and available in the revised birth certificate format were chosen for inclusion in this analysis. Patient demographics included age (<20, 20–24, 25–29, 30–34, and ≥35 years); race/ethnicity (non-Hispanic white, non-Hispanic black, non-Hispanic other, and Hispanic); highest level of education (<ninth grade through professional degree); marital status (married or unmarried); and year of delivery.


Obstetrical factors included trimester of presentation to prenatal care and gestational age at delivery. The association between attempted mode of delivery and maternal clinical and demographic variables were compared using the χ 2 test. To account for the effect of clinical, obstetric, and demographic factors on the probability of planned mode of delivery, we developed log linear regression models including factors that were clinically important and/or statistically significant on univariable analysis. Results are reported as a risk ratio with a 95% confidence interval.


As a secondary analysis, we evaluated the risk factors associated with the diagnosis of gastroschisis to provide an up-to-date analysis on the epidemiology of this anomaly. We compared pregnancies with and without gastroschisis and analyzed maternal obstetric, medical, and demographic factors. For this analysis the only inclusion criteria were live births between 2005 and 2013 and gestational age between 24 and <42 weeks. Data on insurance status, body mass index (kilograms per square meter), and sexually transmitted infections were included in this analysis but are available only for the years 2011 through 2013.


We used χ 2 tests to compare the relationship between risk factors for gastroschisis and the outcome and included statistically significant characteristics in an adjusted log linear regression model. A sensitivity analysis of the log linear model restricted to the years 2011–2013 to include the additional covariates available only during those years was performed. Additionally, the proportion of deliveries occurring from 34 to 42 weeks that are late preterm, early term, and full term are described by year.


A sensitivity analysis of births from 2009 through 2013 evaluating the rate of attempted labor including only those states that utilized the revised birth certificate as of 2009 was performed; given that there was a gradual uptake of states using the revised birth certificate on an annual basis, this sensitivity analysis controls for the potential bias of the shifting sampling frame. Additionally, to assess the validity of our classification of attempted vaginal delivery, we repeated the sensitivity analysis using a separate variable indicating trial of labor and excluding diagnoses of fetal intolerance of labor and long labor, given concerns related to the quality of these latter diagnoses. Finally, we assessed temporal trends in the diagnosis of gastroschisis in the restricted cohorts of states using the revised birth certificate as of 2009 to similarly account for the changing sampling frame. All analyses were performed using SAS version 9.4 (SAS Institute, Cary, NC).




Results


For the primary analysis evaluating factors associated with planned cesarean delivery vs attempted vaginal delivery, a total of 5985 pregnancies between 2005 and 2013 had a diagnosis of gastroschisis, met inclusion criteria, and were included. Of this cohort, 63.5% (3800 pregnancies) had an attempted vaginal delivery and 36.5% (2185) underwent a planned cesarean delivery. The rate of attempted vaginal delivery increased from 59.7% in 2005 to 68.8% in 2013 ( P < .001).


In addition to the year of delivery, other factors significantly associated with the type of delivery included race and parity; Hispanic women were less likely (58.8%) and parous women more likely (68.8%) to attempt vaginal delivery than non-Hispanic white (64.7%) and nulliparous women, respectively (60.8).


Earlier gestational age at delivery was associated with a lower probability of attempted vaginal delivery with women ≥28 to <32 weeks attempting vaginal delivery in 52.9% of cases ( Table 1 ). Other significant factors included gestational age at prenatal care entry. In the adjusted log linear model, the following factors retained significance: (1) the final years of the study (2011–2013) were associated with anincreased probability of vaginal delivery relative to 2005; (2) multiparity was associated with an increased probability of attempted vaginal delivery compared with nulliparity; (3) Hispanic ethnicity and earlier gestational age at delivery were associated with a decreased probability of attempted vaginal delivery compared with non-Hispanic white race and later gestational age, respectively.



Table 1

Univariate and adjusted analysis of attempted vaginal vs planned cesarean delivery






































































































































































































































































































































































































Attempted vaginal delivery, %, n Univariate analysis Multivariable log linear model
P value Adjusted risk ratio 95% confidence interval
All patients 63.5 (3800)
Live-born parity < .001
Nulliparous 60.8 (2419) 1.00 Referent
Parous 68.8 (1358) 1.14 (1.09–1.19)
Unknown 65.7 (23) 1.05 (0.82–1.34)
Maternal age, y .021
<20 60.6 (1163) 1.02 (0.95–1.09)
20–24 65.0 (1736) 1.04 (0.98–1.10)
25–29 65.2 (632) 1.00 Referent
30–34 63.9 (200) 0.97 (0.88–1.07)
>34 60.5 (69) 0.91 (0.78–1.06)
Gestational age, wks < .001
≥28 to <32 52.9 (146) 1.00 Referent
≥32 to <36 59.9 (1152) 1.15 (1.02–1.29)
≥36 to <39 66.2 (1990) 1.27 (1.14–1.43)
≥39 to <42 65.7 (512) 1.26 (1.11–1.42)
Highest level of education .941
Less than ninth grade 62.2 (120) 1.00 Referent
Ninth grade to 12 grade 62.4 (961) 1.01 (0.89–1.13)
High school graduate 63.4 (1340) 0.99 (0.89–1.12)
Some college credit 63.8 (894) 1.00 (0.88–1.12)
Associate degree 65.8 (179) 1.03 (0.89–1.18)
BS degree 64.9 (211) 1.05 (0.91–1.21)
MS degree 64.8 (46) 1.07 (0.87–1.32)
Doctorate/professional 71.4 (10) 1.13 (0.81–1.59)
Unknown 68.4 (39) 0.96 (0.77–1.20)
Year < .001
2005 59.7 (188) 1.00 Referent
2006 57.0 (274) 0.96 (0.85–1.08)
2007 57.4 (322) 0.98 (0.87–1.10)
2008 63.4 (426) 1.07 (0.96–1.20)
2009 60.6 (425) 1.03 (0.92–1.14)
2010 63.4 (471) 1.06 (0.96–1.18)
2011 65.9 (563) 1.11 (1.00–1.23)
2012 67.5 (570) 1.14 (1.03–1.26)
2013 68.8 (561) 1.16 (1.04–1.28)
Marital status .452
Married 64.2 (1099) 1.00 Referent
Unmarried 63.2 (2701) 1.01 (0.96–1.06)
Race < .001
Non-Hispanic white 64.7 (2361) 1.00 Referent
Non-Hispanic black 64.6 (369) 0.97 (0.91–1.04)
Non-Hispanic other 67.5 (158) 1.03 (0.93–1.13)
Hispanic 58.8 (875) 0.91 (0.87–0.96)
Unknown 82.2 (37) 1.27 (1.09–1.48)
Prenatal care entry .001
First to third month 61.5 (2082) 1.00 Referent
Fourth to sixth month 64.9 (1030) 1.06 (1.01–1.11)
Seventh to final month 69.4 (263) 1.12 (1.05–1.21)
No care 71.7 (99) 1.18 (1.05–1.32)
Unknown 66.1 (326) 1.10 (1.03–1.18)
Preexisting diabetes .374
Present 50.0 (6) 0.78 (0.44–1.37)
Absent 63.5 (3794) 1.00 Referent
Chronic hypertension .154
Present 76.9 (20) 1.27 (1.03–1.57)
Absent 63.4 (3780) 1.00 Referent
Gestational diabetes .650
Present 54.0 (47) 0.84 (0.69–1.02)
Absent 63.6 (3753) 1.00 Referent
Gestational hypertension .959
Present 63.7 (79) 1.04 (0.92–1.19)
Absent 62.2 (3721) 1.00 Referent

Friedman et al. Gastroschisis, 2005–2013. Am J Obstet Gynecol 2016 .


For the epidemiologic analysis of factors associated with gastroschisis, 7683 pregnancies with the anomaly and 24,829,094 pregnancies without the anomaly were included. The overall incidence was 3.1 cases per 10,000 pregnancies and ranged from 2.9 to 3.2 during the study period. The univariable comparison is demonstrated in Table 2 . In this cohort gastroschisis occurred primarily among young women; 74.0% of cases were diagnosed in women younger than 25 years.



Table 2

Prevalence of and risk factors associated with gastroschisis
























































































































































































































































































































































































































































































































































































Gastroschisis incidence Gastroschisis No gastroschisis
Per 10,000 % n % n
All patients 3.1 7683 24,829,094
Parity
Nulliparous 4.9 62.5 4798 39.8 9,875,617
Parous 1.9 36.9 2830 59.6 14,801517
Unknown 3.6 0.7 55 0.6 151,960
Age, y
<20 10.2 30.4 2336 9.24 2,291,664
20–24 5.6 43.6 3348 24.1 5,985,336
25–29 1.9 17.3 1327 28.2 7,004,452
30–34 0.8 6.1 472 23.9 5,943,870
>34 0.6 2.6 200 14.5 3,603,772
Highest level of education
Less than ninth grade 2.0 3.3 255 5.1 1,267,877
Ninth grade to 12th grade 5.3 25.3 1941 14.7 3,657,185
High school graduate 4.3 35.4 2722 25.4 6,303,068
Some college credit 3.5 22.7 1744 20.1 4,989,457
Associate degree 2.0 4.7 361 7.2 1,781,608
BS degree 1.0 5.7 442 17.2 4,276,058
MS degree 0.6 1.4 107 7.1 1,757,605
Doctorate/professional 0.4 0.3 20 2.0 493,825
Unknown 3.0 1.2 91 1.2 302,411
Year
2005 3.2 5.3 404 5.1 1,274,557
2006 2.9 7.8 598 8.4 2,082,629
2007 3.1 9.5 729 9.6 2,381,081
2008 3.1 11.2 859 11.0 2,743,047
2009 3.2 11.8 900 11.3 2,800,219
2010 3.0 12.3 943 12.4 3,091,522
2011 3.2 14.1 1084 13.6 3,388,437
2012 3.2 14.5 1116 14.1 3,500,152
2013 2.9 13.7 1050 14.4 3,567,450
Marital status
Married 1.6 29.9 2300 59.7 14,822,523
Unmarried 5.4 70.1 5383 40.3 10,006,571
Race
Non-Hispanic white 3.5 59.9 4604 52.6 13,060,137
Non-Hispanic black 2.4 10.4 799 13.6 3,374,368
Non-Hispanic other 1.8 3.9 296 6.5 1,620,916
Hispanic 2.9 25.0 1924 26.5 6,578,384
Unknown 3.1 0.8 60 0.8 195,289
Prenatal care presentation
1 st to 3 rd month 2.5 55.3 4251 67.8 16,845,517
4 th to 6 th month 4.2 26.6 2042 19.6 4,856,012
7 th to final month 4.4 6.4 492 14.5 1,121,167
No care 5.6 3.0 227 1.6 407,948
Unknown 4.2 8.7 671 6.4 1,598,450
Multiple gestation
Singleton 3.1 97.8 7512 96.6 23,979,384
Twin 2.0 2.1 166 3.3 813,852
Triplet or higher 1.4 0.1 5 0.1 35,858
Pregestational diabetes
Present 1.5 0.4 27 0.7 175,310
Absent 3.1 99.2 7623 99.1 24,610,950
Unknown 7.7 0.4 33 0.2 42,834
Chronic hypertension
Present 1.2 0.5 39 1.3 317,207
Absent 3.1 99.1 7611 98.6 24,469,053
Unknown 7.7 0.4 33 0.2 42,834
Smoking
Present 7.4 19.7 1516 8.3 2,052,424
Absent 2.7 67.4 5179 78.1 19,399,146
Unknown 2.9 12.9 988 13.6 3,377,524
Body mass index (kg/m 2 ) a
Underweight (<18.5) 5.9 7.0 228 3.7 387,105
Normal (18.5–24.9) 3.9 57.0 1854 44.9 4,695,030
Overweight (25.0–29.9) 2.6 20.2 655 24.4 2,547,371
Obesity (30.0–34.9) 1.8 7.4 241 12.7 1,331,599
Obesity (35.0–39.9) 1.4 2.7 88 6.0 624,758
Obesity (≥ 40) 0.9 1.2 40 4.1 426,308
Unknown 3.2 4.4 144 4.3 443,868
Chlamydia during pregnancy a
Present 3.0 95.6 3109 97.9 10,252,322
Absent 6.8 4.4 141 2.9 206,833
Insurance status a
Medicaid 4.5 62.1 2017 43.1 4,502,049
Private 1.9 28.2 918 46.4 4,855,913
Self-pay 1.8 2.5 80 4.2 442,258
Other 3.6 5.7 185 4.9 513,040
Unknown 3.5 1.5 50 1.4 142,779

Incidence listed is number of cases per 10,000 births.

Friedman et al. Gastroschisis, 2005–2013. Am J Obstet Gynecol 2016 .

a Only 2011–2013 data are available. All comparisons were statistically significant with P < .001.



The risk ratio in the adjusted model for age <20 years was 3.46 (95% confidence interval, 3.19–3.75) ( Table 3 ) compared with women aged 25–29 years. Other factors associated with gastroschisis in the adjusted model included smoking (risk ratio, 1.61, 95% confidence interval, 1.51–1.72) and being unmarried (risk ratio, 1.67, 95% confidence interval, 1.57–1.77). High school graduation as highest educational attainment was significantly associated with gastroschisis (risk ratio, 1.40, 95% confidence interval, 1.23–1.59) with less than a ninth grade education as the referent; ninth to 12th grade education, some college, and an associate degree were also associated with increased risk for gastroschisis, whereas a master’s degree or doctorate/professional degree were associated with a decreased risk.



Table 3

Multivariable models of factors associated with gastroschisis





































































































































































































































































































































































































































2005–2013 model 2011–2013 model
Risk ratio 95% confidence interval Risk ratio 95% confidence interval
Parity
Nulliparous 1.00 Referent 1.00 Referent
Parous 0.69 (0.65–0.72) 0.71 (0.65–0.76)
Unknown 1.08 (0.83–1.41) 1.23 (0.80–1.87)
Age, y
<20 3.46 3.19–3.75 2.86 (2.52–3.24)
20–24 2.23 2.08–2.39 2.07 (1.87–2.29)
25–29 1.00 Referent 1.00 Referent
30–34 0.51 0.46–0.57 0.53 (0.46–0.62)
>34 0.38 0.33–0.44 0.41 (0.33–0.51)
Highest level of education
Less than ninth grade 1.00 Referent 1.00 Referent
Ninth grade to 12th grade 1.34 (1.17–1.53) 1.68 (1.31–2.17)
High school graduate 1.40 (1.23–1.59) 1.79 (1.39–2.29)
Some college credit 1.44 (1.26–1.65) 1.81 (1.40–2.33)
Associate degree 1.28 (1.08–1.50) 1.59 (1.19–2.13)
BS degree 0.92 (0.78–1.08) 1.10 (0.82–1.47)
MS degree 0.69 (0.55–0.87) 0.92 (0.64–1.32)
Doctorate/professional 0.51 (0.32–0.82) 0.46 (0.22–0.97)
Year
2005 1.00 Referent
2006 0.93 (0.82–1.06)
2007 0.98 (0.87–1.11)
2008 1.02 (0.90–1.15)
2009 1.06 (0.94–1.19)
2010 1.03 (0.92–1.16)
2011 1.12 (1.00–1.25) 1.00 Referent
2012 1.14 (1.02–1.28) 1.02 (0.94–1.11)
2013 1.09 (0.97–1.22) 0.97 (0.90–1.06)
Marital status
Married 1.00 Referent
Unmarried 1.67 (1.57–1.77)
Race
Non-Hispanic white 1.00 Referent 1.00 Referent
Non-Hispanic black 0.44 (0.41–0.48) 0.49 (0.44–0.55)
Non-Hispanic other 0.81 (0.72–0.91) 0.80 (0.67–0.95)
Hispanic 0.69 (0.64–0.73) 0.71 (0.64–0.78)
Multiple gestation
Singleton 1.00 Referent 1.00 Referent
Multiple gestation 1.01 (0.86–1.17) 0.95 (0.75–1.21)
Pregestational diabetes
Present 0.73 (0.50–1.07) 1.17 (0.72–1.89)
Absent 1.00 Referent 1.00 Referent
Unknown 2.20 (1.56–3.10) 1.20 (0.57–2.53)
Chronic hypertension
Present 0.61 (0.44–0.84) 0.99 (0.66–1.48)
Absent 1.00 Referent 1.00 Referent
Smoking
Present 1.61 (1.51–1.72) 1.70 (1.54–1.87)
Absent 1.00 Referent 1.00 Referent
Unknown 1.05 (0.98–1.13) 0.97 (0.83–1.13)
Body mass index, kg/m 2 a
Underweight (<18.5) N/A N/A 1.04 (0.91–1.20)
Normal (18.5–24.9) 1.00 Referent
Overweight (25.0–29.9) 0.70 (0.65–0.77)
Obesity (30.0–34.9) 0.49 (0.43–0.56)
Obesity (35.0–39.9) 0.38 (0.31–0.47)
Obesity (≥40) 0.26 (0.19–0.36)
Unknown 0.93 (0.79–1.11)
Chlamydia during pregnancy a
Present N/A N/A 1.00 Referent
Absent 1.17 (0.99–1.39)
Insurance status a
Medicaid 1.09 (1.00–1.20)
Private N/A N/A 1.00 Referent
Self-pay 0.73 (0.58–0.93)
Other 1.17 (0.99–1.38)
Unknown 1.13 (0.85–1.52)

Only gold members can continue reading. Log In or Register to continue

Stay updated, free articles. Join our Telegram channel

May 2, 2017 | Posted by in GYNECOLOGY | Comments Off on Gastroschisis: epidemiology and mode of delivery, 2005–2013

Full access? Get Clinical Tree

Get Clinical Tree app for offline access