Route of delivery and neonatal birth trauma

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Route of delivery and neonatal birth trauma Charmaine K. Moczygemba, MD; Pangaja Paramsothy, MPH; Susan Meikle, MD, MSPH; Athena P. Kourtis, MD, PhD, MPH; Wanda D. Barfield, MD, MPH; Elena Kuklina, MD, PhD; Samuel F. Posner, PhD; Maura K. Whiteman, PhD; Denise J. Jamieson, MD, MPH OBJECTIVE: We sought to examine rates of birth trauma in 2 groupings

(all International Classification of Diseases, Ninth Revision codes for birth trauma, and as defined by the Agency for Healthcare Research and Quality Patient Safety Indicator [PSI]) among infants born by vaginal and cesarean delivery. STUDY DESIGN: Data on singleton infants were obtained from the

2004-2005 Healthcare Cost and Utilization Project Nationwide Inpatient Sample.

Compared with vaginal, cesarean delivery was associated with increased odds of PSI birth trauma (odds ratio [OR], 1.71), primarily due to an increased risk for “other specified birth trauma” (OR, 2.61). Conversely, cesarean delivery was associated with decreased odds of all birth trauma (OR, 0.55), due to decreased odds of clavicle fractures (OR, 0.07), brachial plexus (OR, 0.10), and scalp injuries (OR, 0.55). CONCLUSION: Infants delivered by cesarean are at risk for different

types of birth trauma from infants delivered vaginally.

RESULTS: The rates of Agency for Healthcare Research and Quality PSI

and all birth trauma were 2.45 and 25.85 per 1000 births, respectively.

Key words: neonatal birth trauma, patient safety, route of delivery

Cite this article as: Moczygemba CK, Paramsothy P, Meikle S, et al. Route of delivery and neonatal birth trauma. Am J Obstet Gynecol 2010;202:361.e1-6.

C

esarean delivery is the most common major surgical procedure in the United States and rates have increased from 22.8% in 1989 to 30.3% in 2005.1 There are known risks to mother and fetus during both vaginal and cesarean deliveries. Although a number of studies examine maternal safety associated with cesarean delivery, there are few studies that address neonatal safety. In the era of rapidly increasing cesarean delivery rates, neonatal safety data are urgently needed to monitor the quality of care and better counsel obstetric patients. In 2000, the Institute of Medicine published “To Err Is Human: Building a Safer Health System,” which focused at-

tention on the importance of patient safety in all fields of medicine.2 In response, the Agency for Healthcare Research and Quality (AHRQ) has developed a group of Patient Safety Indicators (PSIs). A PSI is a set of International Classification of Diseases, Ninth Revision (ICD-9) codes that represent outcomes considered avoidable through practice modification. These indicators were chosen by a group of experts through literature review, consensus development, and public comment, but have not been validated.3 A PSI was developed for birth trauma and included 7 types of neonatal birth trauma. Our study uses this AHRQ PSI for examining national rates of birth

trauma. We also examine another clinical grouping of birth trauma codes (all birth trauma) made up of all codes found in the birth trauma section of the ICD-9 coding manual, to capture the total amount of neonatal birth trauma in the United States. In addition, we examine individual types of birth trauma. Furthermore, potential associations of birth trauma with clinical and demographic factors such as route of delivery, birthweight, and presence of fetal distress are examined. We hypothesized that the rates of individual types of neonatal birth trauma, rather than any 1 grouping, would vary by route of delivery.

M ATERIALS AND M ETHODS From the Department of Gynecology and Obstetrics, Emory University (Drs Moczygemba and Jamieson), Atlanta, GA; the Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention (Drs Kourtis, Barfield, Posner, Whiteman, and Jamieson), Atlanta, GA; and Northrop Grumman Civilian Group (Dr Kuklina), Atlanta, GA; Contraceptive Research And Development Program, Arlington, VA (Ms Paramsothy); and Contraceptive and Reproductive Health Branch/National Institutes of Health (the Eunice Kennedy Shriver National Institute of Child Health and Human Development), Bethesda, MD (Dr Meikle). Presented at the District IV Meeting of the American College of Obstetricians and Gynecologists, Orlando, FL, Sept. 5-7, 2008. Received June 9, 2009; revised Sept. 12, 2009; accepted Nov. 14, 2009. Reprints: Charmaine K. Moczygemba, MD, Department of Gynecology and Obstetrics, Emory School of Medicine, 69 Jesse Hill Jr Dr., Fourth Floor, Atlanta, GA 30303. [email protected]. 0002-9378/$36.00 • © 2010 Mosby, Inc. All rights reserved. • doi: 10.1016/j.ajog.2009.11.041

Hospital discharge data from the Nationwide Inpatient Sample (NIS), 20042005, were obtained from the Healthcare Cost and Utilization Project. The Healthcare Cost and Utilization Project is a group of health care databases and related software tools that were developed through a partnership with private and public state level data collection organizations and sponsored by the AHRQ. The NIS is the largest all-payer inpatient care database publicly available in the United States. The sampling universe for NIS includes US community hospitals that are

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open during any part of the calendar year and are designated as community hospitals by the American Hospital Association Annual Survey of Hospitals. Community hospitals are defined as all nonfederal general and specialty hospitals, with average length of stays ⬍30 days, and whose facilities are open to the public. This definition includes specialty hospitals such as orthopedic, pediatric, obstetrics-gynecology, and ear-nosethroat institutions, as well as public hospitals and academic medical centers. A hospital is considered to be a teaching hospital if it has an American Medical Association-approved residency program, is a member of the Council of Teaching Hospitals, or has a ratio of fulltime equivalent interns and residents to beds of ⱖ .25. Veterans hospitals and other federal hospitals, rehabilitation hospitals, psychiatric hospitals, and alcohol/chemical dependency treatment facilities are not included in the sample. Data are gathered from all community hospitals within each participating state. Hospitals may vary from year to year based on state participation, but this change is accounted for by the below sampling strategy. In 2004 and 2005, 37 states contributed data.4 For each year, the NIS is designed to approximate a 20% stratified sample of community hospitals in the United States and contains discharge data for approximately 8 million hospital stays from ⬎1000 hospitals. The sampling frame for NIS uses 5 strata: type of ownership, number of hospital beds, teaching status, urban or rural location, and region of the country. For each sampled hospital, 100% of the discharges are retained. These sampling probabilities are used to create a “weight” for each hospital so when appropriate statistical tools are used, estimates reflect a national sample of community hospitals. That is why we present weighted data, not unweighted data. For each change to the sampling frame, AHQR compares individual years of the NIS with the corresponding National Hospital Discharge Survey and with the Medicare Provider Analysis and Review file to check for consistency and validate the dataset. 361.e2

www.AJOG.org Hospital discharge diagnoses were classified using the ICD-9, Clinical Modification (ICD-9-CM) codes. Singleton live born infants were identified using ICD-9-CM diagnosis codes and classified as either vaginal birth (V30.00, V39.00) or cesarean birth (V30.01, V39.01). Birthweight was defined as low (764.01-764.08, 764.11-764.18, 765.01765.08, 765.11-765.18), high (766.0, 766.1), or average. Since there are no specific codes for average birthweight, newborns without codes specifying low birthweight or high birthweight were considered average. Presence of fetal distress was defined by ICD-9-CM codes 763.81, 763.82, 763.83, 768.2, 768.3, and 768.4. Neonatal birth traumas were defined as subdural and cerebral hemorrhage (767.0), epicranial subaponeurotic hemorrhage (767.11), other injuries to scalp (767.19), fracture of clavicle (767.2), other injures to skeleton (767.3), injury to spine and spinal cord (767.4), facial nerve injury (767.5), injury to brachial plexus (767.6), other cranial and peripheral nerve injuries (767.7), other specified birth trauma (767.8), and birth trauma unspecified (767.9). Other specified birth trauma (767.8) includes hematoma or injury to sternocleidomastoid; hematoma or rupture of spleen, liver; teste; vulva; viscera; kidney or stomach; injury or damage to eye or traumatic glaucoma; fetal laceration by scalpel. Other injuries to scalp (767.19) included caput succedaneum, cephalohematoma, and chignon (from vacuum extraction). If an infant had a diagnosis of subdural and cerebral hemorrhage and was defined as preterm (765.01765.09, 765.11-765.19, 765.21-765.28), then the diagnosis was not considered a birth trauma. If an infant had a diagnosis of other injuries to skeleton or injury to spine and spinal cord and had a diagnosis of osteogenesis imperfecta (756.51), then the diagnosis was not considered a birth trauma. Birth traumas were examined in 2 groups as well as individually. The AHRQ PSI birth trauma includes the 7 types of birth trauma: (1) subdural and cerebral hemorrhage, (2) epicranial subaponeurotic hemorrhage, (3) other inju-

American Journal of Obstetrics & Gynecology APRIL 2010

ries to skeleton, (4) injury to spine and spinal cord, (5) other cranial and peripheral nerve injuries, (6) other specified birth trauma, and (7) birth trauma unspecified. In addition, we created and examined a new all-inclusive group of neonatal birth trauma, called “all birth trauma,” which includes the 7 PSI birth traumas as well as 4 additional birth traumas: (1) other injuries to scalp, (2) fracture to clavicle, (3) facial nerve injury, and (4) injury to brachial plexus. Primary payer was defined as public (Medicare/Medicaid), private (private insurance), or other (self-pay, no insurance). For each hospital, the number of liveborn singleton deliveries per year were categorized as ⱕ400, 401-1300, or ⬎1300. Hospital teaching type and location were combined and defined as rural, urban nonteaching, and urban teaching. To account for the complex sampling design, we used software (SAS-callable SUDAAN, v. 9.1; Research Triangle Institute, Research Triangle Park, NC) to analyze the data. Rates, along with the 95% confidence interval (CI), were calculated per 1000 singleton live hospital births. Logistic regression was used to estimate both unadjusted and adjusted odds ratio (aOR) as well as corresponding 95% CI. Interaction between route of delivery and neonatal birthweight, and route of delivery and presence of fetal distress, was evaluated and considered to be present if P ⬍ .01. Programming and data results were confirmed by 2 independent researchers. Since the NIS data do not contain personal identifiers and are publicly available administrative data, the Centers for Disease Control and Prevention determined this research to be exempt research not requiring review by an institutional review board.

R ESULTS Our study population included a weighted sample of 8,176,523 live singleton newborns born in a hospital in 2004 and 2005. The proportion of singleton neonates born by cesarean delivery was 29.52%. The proportions of low and high birthweight infants were 4.44% and 5.77%, respectively. The proportion of

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TABLE 1

Neonatal characteristics and birth trauma rates na

Variable Sex of infant

nb

Percent

AHRQ PSI birth trauma ratec (95% CI)

Unadjusted OR for PSI birth trauma (95% CI)

All birth trauma ratec (95% CI)

Unadjusted OR for all birth trauma (95% CI)

d

.......................................................................................................................................................................................................................................................................................................................................................................

Male

861,461

4,176,147

51.19

2.63 (2.35–2.91)

1.16 (1.09–1.24)

28.74 (27.25–30.22)

1.27 (1.23–1.31)

Female

821,455

3,982,713

48.80

2.27 (2.00–2.54)

Referent

22.80 (21.41–24.19)

Referent

....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................

Primary payer

.......................................................................................................................................................................................................................................................................................................................................................................

Public

699,742

3,385,847

41.41

2.23 (2.00–2.46)

0.90 (0.75–1.07)

25.38 (23.55–27.21)

0.99 (0.90–1.09)

Private

865,135

4,201,515

51.39

2.63 (2.25–3.02)

1.06 (0.87–1.30)

26.26 (24.68–27.85)

1.03 (0.93–1.13)

Other

121,657

589,161

7.20

2.48 (2.07–2.89)

Referent

25.58 (23.28–27.88)

Referent

....................................................................................................................................................................................................................................................................................................................................................................... ....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................

Delivery route

.......................................................................................................................................................................................................................................................................................................................................................................

Cesarean

498,451

2,413,979

29.52

3.46 (3.13–3.79)

1.71 (1.56–1.87)

17.07 (16.02–18.11)

0.57 (0.55–0.59)

1,188,083

5,762,544

70.48

2.03 (1.77–2.29)

Referent

29.53 (27.92–31.13)

Referent

.......................................................................................................................................................................................................................................................................................................................................................................

Vaginal

................................................................................................................................................................................................................................................................................................................................................................................

Birthweight

.......................................................................................................................................................................................................................................................................................................................................................................

Low

75,053

362,921

4.44

3.26 (2.78–3.75)

1.42 (1.23–1.63)

15.94 (14.55–17.34)

0.63 (0.59–0.68)

1,513,724

7,341,681

89.79

2.30 (2.04–2.57)

Referent

25.04 (23.67–26.40)

Referent

97,757

471,921

5.77

4.17 (3.60–4.74)

1.81 (1.60–2.05)

46.09 (43.33–48.84)

1.88 (1.79–1.98)

.......................................................................................................................................................................................................................................................................................................................................................................

Normal

.......................................................................................................................................................................................................................................................................................................................................................................

High

................................................................................................................................................................................................................................................................................................................................................................................

Fetal distress

.......................................................................................................................................................................................................................................................................................................................................................................

Present

10,080

48,855

0.60

6.75 (5.02–8.48)

2.79 (2.13–3.65)

64.15 (52.61–75.69)

2.61 (2.17–3.14)

Absent

1,676,454

8,127,668

99.40

2.43 (2.16–2.69)

Referent

25.62 (24.26–26.98)

Referent

....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................

Admission on weekendd

.......................................................................................................................................................................................................................................................................................................................................................................

Yes

342,303

1,659,934

20.30

2.64 (2.32–2.95)

1.10 (1.01–1.18)

28.57 (26.96–30.18)

1.14 (1.11–1.17)

1,344,230

6,516,584

79.70

2.41 (2.14–2.67)

Referent

25.16 (23.80–26.51)

Referent

.......................................................................................................................................................................................................................................................................................................................................................................

No

................................................................................................................................................................................................................................................................................................................................................................................

No. of singleton deliveries/y at hospitald

.......................................................................................................................................................................................................................................................................................................................................................................

ⱕ400

83,916

427,354

5.23

1.98 (1.50–2.47)

0.79 (0.60–1.04)

19.93 (17.78–22.08)

0.76 (0.67–0.86)

358,435

1,736,210

21.23

2.35 (1.93–2.76)

0.93 (0.75–1.16)

26.29 (23.87–28.71)

1.01 (0.89–1.13)

1,244,183

6,012,958

73.54

2.52 (2.18–2.85)

Referent

26.14 (24.40–27.89)

Referent

.......................................................................................................................................................................................................................................................................................................................................................................

401–1300

.......................................................................................................................................................................................................................................................................................................................................................................

ⱖ1301

................................................................................................................................................................................................................................................................................................................................................................................

Hospital location and teaching typed

.......................................................................................................................................................................................................................................................................................................................................................................

Rural

185,118

937,600

11.47

2.32 (1.62–3.02)

0.81 (0.57–1.14)

22.28 (19.95–24.61)

0.83 (0.72–0.96)

Urban nonteaching

771,587

3,706,117

45.33

2.10 (1.79–2.42)

0.73 (0.59–0.92)

25.96 (23.94–27.98)

0.97 (0.86–1.10)

Urban teaching

729,829

3,532,807

43.20

2.86 (2.38–3.34)

Referent

26.68 (24.37–28.99)

Referent

....................................................................................................................................................................................................................................................................................................................................................................... ....................................................................................................................................................................................................................................................................................................................................................................... ................................................................................................................................................................................................................................................................................................................................................................................

AHRQ, Agency for Healthcare Research and Quality; CI, confidence interval; OR, odds ratio; PSI, Patient Safety Indicator. a

Unweighted number of live singleton births; b Weighted number of live singleton births; c Rate is per thousand singleton live births; d Sample size does not equal to 8,176,523, due to missing date and/or rounding error.

Moczygemba. Route of delivery and neonatal birth trauma. Am J Obstet Gynecol 2010.

infants with fetal distress prior to delivery was 0.60% (Table 1). The rate of AHRQ PSI birth trauma was 2.45 per 1000 births (95% CI, 2.19 –2.72) and the rate of all birth trauma was 25.85 per 1000 births (95% CI, 24.47–27.23). In unadjusted analyses, infants who were

male, delivered by cesarean delivery, low birthweight, high birthweight, born with documented fetal distress, or admitted on a weekend were all groups at increased odds for AHRQ PSI birth trauma. Infants born in urban nonteaching hospitals had decreased odds of AHRQ PSI birth

trauma. Similarly, infants who were male, high birthweight, born with documented fetal distress, or admitted on a weekend were all groups at increased odds for all birth trauma. Infants born by cesarean delivery, low birthweight, in a hospital with ⱕ400 deliveries per year, or in a rural hos-

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www.AJOG.org not significantly different between cesarean and vaginal deliveries (aOR, 0.83; 95% CI, 0.67–1.04) (Table 3). When we examined all birth trauma outcome group, cesarean delivery was consistently associated with a reduced odds of birth trauma compared to vaginal delivery across all fetal distress and birthweight subgroups (Table 3).

FIGURE

Distribution of neonatal birth trauma

C OMMENT

Distribution of all neonatal birth trauma and birth trauma considered to be a Patient Safety Indicator (PSI) by Agency for Healthcare Research and Quality (AHRQ) EGA, estimated gestational age. Moczygemba. Route of delivery and neonatal birth trauma. Am J Obstet Gynecol 2010.

pital were at decreased odds for all birth trauma (Table 1). The birth trauma category “other injuries to scalp,” which is not included in the AHRQ PSI, accounted for a majority of all birth trauma (78.24%) in the United States. AHRQ PSI birth trauma accounted for 9.62% of total birth trauma. The largest type within the AHRQ PSI birth trauma group was “other specified birth trauma” (6.34%) (Figure). Overall, when comparing cesarean delivery with vaginal delivery, the odds of AHRQ PSI birth trauma were higher for cesarean delivery (aOR 1.65; 95% CI, 1.51–1.81) whereas the odds of all birth trauma were lower for cesarean delivery (aOR 0.55; 95% CI, 0.53– 0.58). The rates of other injuries to scalp, fracture to clavicle, and injury to brachial plexus were all lower among cesarean deliveries. The rate of “other specified birth trauma” was lower in vaginal delivery. The rates of epicranial subaponeurotic hemorrhage, subdural and cerebral hemorrhage, other injuries to skeleton, birth trauma unspecified, and facial 361.e4

nerve injury were similar among cesarean and vaginal deliveries. The weighted samples for “injury to spine and spinal cord” and “other cranial or peripheral nerve” were too small to calculate rates and compare (Table 2). The relationship between route of delivery and AHRQ PSI birth trauma varied according to the presence or absence of fetal distress at delivery and according to birthweight (P interaction ⬍ .01). When fetal distress was absent, the odds of AHRQ PSI birth traumas were higher among cesarean deliveries compared with vaginal deliveries (aOR, 1.66; 95% CI, 1.52–1.82), whereas in the presence of fetal distress the odds of PSI birth trauma were not significantly different when comparing cesarean and vaginal deliveries (aOR, 1.09; 95% CI, 0.661.80). Among low and average fetal birthweight groups, cesarean delivery was associated with an increased odds of AHRQ PSI birth trauma (aOR, 2.22; 95% CI, 1.71–2.89; and aOR, 1.76; 95% CI, 1.60 –1.93), respectively), whereas the odds of AHRQ PSI birth trauma among large birthweight infants were

American Journal of Obstetrics & Gynecology APRIL 2010

Our study provides nationwide estimates of birth trauma, with approximately 2.6% of births complicated by some type of birth trauma. We also provide a nationwide estimate of the PSI for neonatal birth trauma as defined by AHRQ, which is the only published grouping of birth trauma considered modifiable by changing physician practices. The association between cesarean delivery and neonatal birth trauma changes direction when examining the 2 birth trauma groupings because the association varies by individual type of birth trauma. Compared with vaginal delivery, cesarean delivery was associated with increased odds of PSI birth trauma, primarily due to increased odds for “other specified birth trauma.” Since the driving ICD-9 code includes 11 distinct types of birth trauma that do not have their own separate codes or qualifiers, it is difficult to determine exactly what type of birth trauma is responsible for the positive association between cesarean delivery and neonatal birth trauma. Conversely, cesarean delivery was associated with decreased odds of all birth trauma, primarily due to decreased odds of clavicle fractures and injuries to the brachial plexus and scalp. These 3 codes, which are not included within the AHRQ PSI, have a strong association with vaginal delivery and result in a change in direction of the association of cesarean delivery with all neonatal birth trauma, despite the inclusion of the AHRQ PSI ICD-9 codes within this grouping. The association between route of delivery and birth trauma also varies by fetal characteristics. In the absence of fetal distress and among low or average birth-

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TABLE 2

Specific birth trauma rates Ratea for cesarean delivery (95% CI)

Ratea for vaginal delivery (95% CI)

Subdural and cerebral hemorrhage (767.0)c,d

0.23 (0.18–0.27)

0.19 (0.16–0.22)

1.22 (0.97–1.54)

Epicranial subaponeurotic hemorrhage (massive) (767.11)c

0.15 (0.11–0.18)

0.11 (0.09–0.13)

1.26 (0.93–1.72)

Other injuries to skeleton (767.3)

0.33 (0.23–0.44)

Type of birth trauma (ICD-9 code)

aORb (95% CI) cesarean vs vaginal delivery

................................................................................................................................................................................................................................................................................................................................................................................

................................................................................................................................................................................................................................................................................................................................................................................ c,e

0.34 (0.23–0.44)

0.95 (0.77–1.17)

................................................................................................................................................................................................................................................................................................................................................................................ c f f

Injury to spine or spinal cord (767.4)

N/A

................................................................................................................................................................................................................................................................................................................................................................................ c f

Other cranial or peripheral nerve injury (767.7)

0.04 (0.03–0.06)

N/A

................................................................................................................................................................................................................................................................................................................................................................................ c g

Other specified birth trauma (767.8)

2.61 (2.38–2.85)

1.23 (1.05–1.41)

2.07 (1.84–2.32)

Birth trauma unspecified (767.9)

0.17 (0.08–0.27)

0.15 (0.07–0.23)

1.16 (0.94–1.43)

................................................................................................................................................................................................................................................................................................................................................................................ c ................................................................................................................................................................................................................................................................................................................................................................................ h g

AHRQ PSI birth trauma

3.46 (3.13–3.79)

2.03 (1.77–2.29)

1.65 (1.51–1.81)

13.15 (12.24–14.07)

23.17 (21.64–24.70)

0.55 (0.53–0.58)

Fracture to clavicle (767.2)

0.25 (0.20–0.30)

3.29 (2.98–3.60)

0.07 (0.06–0.09)

Facial nerve injury (767.5)

0.24 (0.20–0.29)

0.22 (0.19–0.25)

1.07 (0.85–1.34)

0.17 (0.13–0.21)

1.49 (1.39–1.58)

0.10 (0.08–0.13)

17.07 (16.02–18.11)

29.53 (27.92–31.13)

0.55 (0.53–0.58)

................................................................................................................................................................................................................................................................................................................................................................................ g

Other injuries to scalp (767.19)

................................................................................................................................................................................................................................................................................................................................................................................ ................................................................................................................................................................................................................................................................................................................................................................................ ................................................................................................................................................................................................................................................................................................................................................................................

Injury to brachial plexus (767.6)

................................................................................................................................................................................................................................................................................................................................................................................ h g

Birth trauma–all

................................................................................................................................................................................................................................................................................................................................................................................

AHRQ, Agency for Healthcare Research and Quality; aOR, adjusted odds ratio; CI, confidence interval; ICD-9, International Classification of Diseases, Ninth Revision; N/A, because of small numbers we were unable to construct multivariate models; PSI, Patient Safety Indicator. a

Adjusted for birthweight, sex, and admission on weekend; b Rates are per thousand singleton births; c AHRQ PSI birth trauma; d Excluding infants weighing ⬍2500 g or estimated gestational age ⬍37 wk, when using AHRQ guidelines for PSIs; e Excluding infants with diagnosis osteogenesis imperfecta, when using AHRQ guidelines for PSIs; f Unstable estimate relative SE ⬎ .3; g Model also adjusted for fetal distress; h Values were calculated from number of neonates with at least 1 type of AHRQ PSI birth trauma or all birth trauma, therefore a neonate with ⬎1 injury would only be counted once.

Moczygemba. Route of delivery and neonatal birth trauma. Am J Obstet Gynecol 2010.

weight babies, cesarean delivery is associated with increased odds of AHRQ PSI birth trauma compared to vaginal delivery. Otherwise, in neonates with fetal distress and large birthweight, the odds of AHRQ PSI are not significantly different between cesarean and vaginal delivery. Cesarean delivery is associated with a reduced odds of all birth trauma compared to vaginal delivery across all fetal distress and birthweight subgroups. Although we are unable to directly assess the validity of the AHRQ PSI as a tool to measure safety, our findings do highlight some limitations and some areas for future research. As mentioned above, the prevailing ICD-9 code “other specified birth trauma,” which makes up 58% of the AHRQ PSI, represents 11 types of birth trauma that are impossible to separate when using administrative data. Additionally, the diagnoses included within the AHRQ PSI, as well as within “other specified birth trauma,” represent a spectrum of severity and long-term morbidity that ranges from inconsequential to sustained neurologic or

physical disability. It is difficult to draw conclusions about safety from a rate that represents a collective group of diagnoses with varying clinical consequence. Finally, our findings demonstrate that the rate of AHRQ PSI birth trauma changes when considering different patient populations and hospital

characteristics. These are variables that are not modifiable. Grobman et al5 examined the AHRQ PSI for obstetric trauma and found those diagnoses to significantly vary by patient and hospital characteristics as well, and they concluded that the obstetric PSI was not a good indicator of patient safety.

TABLE 3

Odds of birth trauma by fetal distress and birthweight Variable

AHRQ PSI birth trauma, aOR (95% CI)

All birth trauma, aOR (95% CI)

Fetal distress

..................................................................................................................................................................................................................................... a a

Present

1.09 (0.66–1.80)

0.40 (0.31–0.52)

Absent

1.66 (1.52–1.82)

0.56 (0.53–0.58)

..................................................................................................................................................................................................................................... a a ..............................................................................................................................................................................................................................................

Birthweight

..................................................................................................................................................................................................................................... b b

Low (⬍2500 g)

2.22 (1.71–2.89)

0.51 (0.45–0.58)

Normal

1.76 (1.60–1.93)

0.58 (0.56–0.61)

High

0.83 (0.67–1.04)

0.39 (0.36–0.58)

..................................................................................................................................................................................................................................... c b b ..................................................................................................................................................................................................................................... d b b ..............................................................................................................................................................................................................................................

AHRQ, Agency for Healthcare Research and Quality; aOR, adjusted odds ratio; CI, confidence interval; PSI, Patient Safety Indicator. a

Adjusted by birthweight, sex, and admission on weekend; b Adjusted for fetal distress, sex, and admission on weekend; c All newborns without International Classification of Diseases, Ninth Revision (ICD-9) codes indicating weight ⬍2500 g (low birthweight) or high birthweight; d ICD-9 codes 766.0 (exceptionally large baby) and 766.1 (other “heavy for dates” infants).

Moczygemba. Route of delivery and neonatal birth trauma. Am J Obstet Gynecol 2010.

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Our study, which utilizes administrative hospital discharge data, has several limitations. Our data are subject to varying coding practices among hospitals, as well as poorly coded conditions of the neonate, such as neonatal distress during labor. Due to its cross-sectional design, causality cannot be inferred. We utilized neonatal hospital discharge records and were unable to link these with maternal discharge data. Therefore, we were unable to examine potentially influential maternal variables such as maternal weight, presence of diabetes, hypertension, age, prior cesarean delivery, and type of vaginal delivery, such as vacuum or forceps, or the occurrence of a failed operative delivery. Perhaps most importantly, we were unable to differentiate between cesarean deliveries without labor and those following a failed trial of labor. Because we used ICD-9-CM discharge codes, we were unable to determine the specific birth traumas represented by the codes for “other injuries to scalp” and “other specified birth trauma.” An important strength of our study is our large sample size, which allowed us to analyze rare outcomes, such as individual types of neonatal birth trauma, and to adjust for and stratify by clinically important factors such as fetal distress and birthweight. Earlier studies examining neonatal birth trauma are limited by small sample sizes and generally focus on a small selection of birth traumas, rather than all known types.6,7 Most of these studies do not examine association with route of delivery.6,8-10 Studies that have examined the association with route of delivery have generally found cesarean to be associated with decreased odds of neonatal birth trauma11,12 but did not examine the effect of birthweight or presence

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www.AJOG.org of fetal distress on this relationship. All of these studies did find rates of the individual types of birth trauma and the associations with route of delivery that are similar to our rates presented here. One exception was the positive association of cesarean delivery with intracranial hemorrhage compared to spontaneous vaginal delivery in a study from California.7 However, the comparison of results is difficult since in our study all vaginal deliveries (spontaneous, vacuum, forceps, or both vacuum and forceps) were considered as a reference group. One study that examined fetal scalp laceration during cesarean delivery did find an association with presence of fetal distress, but the study is limited to only this 1 type of trauma and only in the setting of cesarean delivery.9 To date, much of the research on the safety of cesarean delivery has focused on maternal outcomes; our study adds important information regarding neonatal outcomes associated with route of delivery. An underlying assumption in the practice of obstetrics has been that cesarean delivery is generally safer for the baby. Therefore, when debating the risks and benefits of cesarean delivery, attention has been primarily focused on weighing maternal risks with neonatal benefits. Our study demonstrates that the association between route of delivery and neonatal birth trauma is not a constant in favor of cesarean delivery and actually varies by type of trauma. f ACKNOWLEDGMENTS We thank Aniket Kulkarni and Pooja Bansil for their considerable assistance with data management and analysis.

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American Journal of Obstetrics & Gynecology APRIL 2010

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