|
 |
|
|||||||
|
|||||||||
© 2002 American Public Health Association
RESEARCH AND PRACTICE |
Jeffrey B. Gould is with the School of Public Health, University of California, Berkeley. Gilberto Chavez is with the Maternal and Child Health Branch, California Department of Health Services. Amy R. Marks is, and at the time of the study Hao Liu was, with the School of Public Health, University of California, Berkeley.
Correspondence: Requests for reprints should be sent to Jeffrey B. Gould, MD, MPH, University of California, School of Public Health, 309 Earl Warren Hall, #7360, Berkeley, CA 94720-7360 (e-mail: jgould{at}uclink4.berkeley.edu).
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Objectives. This study assessed the relationship between incomplete birth certificates and infant mortality.
Methods. Birth certificates from California (n = 538 945) were assessed in regard to underreporting of 13 predictors of perinatal outcomes and mortality.
Results. Of the birth certificates studied, 7.25% were incomplete. Underreporting was most common in the case of women at high risk for poor perinatal outcomes and infants dying within the first day. Increasing numbers of unreported items were shown to be associated with corresponding increases in neonatal and postneonatal mortality rates.
Conclusions. Incomplete birth certificates provide an important marker for identifying high-risk women and vulnerable infants. Because data "cleaning" will result in the removal of mothers and infants at highest risk, birth certificate analyses should include incomplete records.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Over the last several decades, vital records have become an increasingly important resource for identifying factors associated with suboptimal perinatal outcomes.1–6 Although several studies have assessed the validity of birth certificate items,7–13 there have been, to our knowledge, no analyses of the relationship between underreporting of birth certificate items and risk of infant death. Because missing birth certificate data tend to be associated with those groups at highest risk for perinatal problems,14 we hypothesized a strong relationship between underreporting of birth certificate data and infant death.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
The present study was based on the 1996 California linked birth–death cohort of 539 629 live births.15 Records in which infant birthweight was listed as less than 500 g (n = 612; 562 infant deaths) were excluded, because 500 g is considered close to the limit of intervention-sensitive viability. Records in which birthweight data were missing (n = 72; 54 infant deaths) were excluded as well.
Gestational age, sex, plurality, method of delivery, payer source, month of prenatal care initiation, and number of prenatal visits were selected for analysis, as were maternal race/ethnicity, natality, age, education, and parity. A data item was considered unreported if its field was empty or involved an official missing notation. Relationships between underreporting and both neonatal mortality (number of deaths in the first 28 days of life per 1000 live-born study infants) and postneonatal mortality (deaths from 28 days until 1 year of life per 1000 infants who survived to 28 days of life) were evaluated.
A logistic model that considered birthweight, method of delivery, plurality, sex, gestational age, month of prenatal care initiation, delivery payer, and maternal race/ethnicity, natality, age, education, and parity was constructed to estimate the independent associations between underreporting of specific variables and neonatal mortality. In addition to traditional risk categories,16 unreported categories were also included. SAS (version 8.0) was used in conducting analyses.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
One or more missing variables were identified in 7.25% of the 538 945 birth certificates. The most frequently unreported variables were gestational age (missing in 3.97% of records), number of prenatal visits (2.68%), month of prenatal care initiation (1.24%), and maternal education (1.19%). Delivery payer source, maternal race, and maternal Hispanic ethnicity were less frequently unreported (missing in 0.21%–0.38% of records). Delivery method, maternal age, maternal birthplace, and parity were absent in only 0.01% to 0.09% of records, and there were only 2 instances in which sex was not reported. Plurality was reported in all cases.
Table 1
demonstrates that the higher a subpopulation' risk for poor perinatal outcomes, the greater the likelihood of underreporting on its birth certificates. In comparison with non-Hispanic Whites, underreporting rates were lower among the Chinese, Korean, and Japanese subpopulations and higher among the African American and Southeast Asian subpopulations. Underreporting rates showed significant increases in the case of mothers who were Hispanic, mothers not born in the United States, teenaged mothers, mothers older than 40 years, and mothers who had less than a high school education.
|
Significant increases in underreporting were also evident in the following groups: women who initiated prenatal care after the first trimester, women who had given birth to 6 or more children, and women whose delivery was not covered by private insurance. Underreporting was strikingly reduced in the case of women with a college education.
In clinical settings, there is often the impression that the sicker an infant and the more likely an infant is to die, the greater the likelihood of the presence of underreporting on a variety of documents (J. B. Gould, unpublished data, March 2000). Analysis of 2 crude proxies for perceived morbidity–risk of death, birthweight and age at death, confirmed this impression. There was an almost 3-fold increase in underreporting rates among infants with birthweights of 500 to 599 g relative to infants with birthweights of 2500 g or higher. Rates of underreporting were 25.2% for infants dying in the first 12 hours of life and 23.6% for infants dying in the second 12 hours of life; there was a dramatic decrease to 13.7% (P < .01) for infants who died during the remainder of the first week.
The great majority of the 39 090 incomplete birth certificates involved only 1 (76.0%) or 2 (87.7%) unreported variables. However, there was a striking relationship between number of unreported variables and both neonatal and postneonatal mortality (Table 2). In the 92.7% of birth certificates without missing data, the neonatal and postneonatal mortality rates were 2.49 and 1.83 per 1000. When only 1 variable was missing, the neonatal mortality rate almost doubled (to 5.35), and the postneonatal mortality rate increased by 42% (to 2.60). The corresponding rates for birth certificates with 6 or more missing items were 229.7 and 46.8 per 1000 live births and 28-day survivors.
|
Unreported gestational age (odds ratio [OR] = 1.69; 95% confidence interval [CI] = 1.2, 2.4), month of prenatal care initiation (OR = 1.79; 95% CI = 1.1, 2.8), maternal education (OR = 2.46; 95% CI = 1.5, 4.1), delivery payer (OR = 2.94; 95% CI = 1.3, 6.5), and method of delivery (OR = 47.1; 95% CI = 12.1, 183.1) were all independently associated with a substantially increased risk of neonatal mortality (P < .0015). Underreporting of race/ethnicity, natality, parity, and maternal age was not independently associated with increased neonatal mortality (P = .37–.82).
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Birth certificates serve both administrative and research functions. Unfortunately, underreporting of data items results in important limitations in terms of the usefulness of vital records for epidemiologic and outcome research. Our results demonstrate that underreporting is not infrequent and often occurs in the case of mothers at highest sociodemographic risk for poor pregnancy outcomes. Furthermore, we identified a striking association between extent of underreporting and both neonatal and postneonatal mortality.
From a research perspective, it is important to use an analytic strategy that allows inclusion of birth certificates with missing data items. A "clean" data set would remove many of the records of those at highest risk for poor outcomes as well as many of the pregnancies resulting in infant death. While it may be possible to impute missing values, the methods must account for the marked elevations in mortality associated with missing data.
Birth certificate registration protocols vary across states and hospitals. Frequently, certificates are submitted in paper and electronic formats that allow missing data fields. Although the specific mechanisms that lead to incomplete birth certificates were not addressed in this study, it is important that we begin to understand and to correct the personal and institutional factors that create the poorest quality records for mothers who are at highest risk.
|
Acknowledgments |
|---|
The Maternal and Child Health Branch of the California Department of Health Services is acknowledged for its support of the Perinatal Profiles Database (contract 99-85027).
We thank Connie Gee for her help in preparing the manuscript.
|
Footnotes |
|---|
J. B. Gould and G. Chavez developed the concept of the study. J. B. Gould developed the study design and was the principal author. G. Chavez assisted with study design refinement and contributed to the interpretation and write-up of the results. A. R. Marks conducted the data analysis and assisted with refinement of the study design and development of the manuscript. H. Liu conducted exploratory data analyses.
Accepted for publication January 11, 2001.
|
References |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
1. Freedman MA, Gay GA, Brockert JE, Potrzebowski PW, Rothwell CJ. The 1989 revisions of the US standard certificates of live birth and death and the US standard report of fetal death. Am J Public Health. 1988;78:168–172.
2. Gould JB. Vital records for quality improvement. Pediatrics. 1999;103(suppl 1):278–290.
3. Mor JM, Alexander GR, Kogan MD, Kieffer EC, Ichiho HM. Similarities and disparities in maternal risk and birth outcomes of white and Japanese-American mothers. Paediatr Perinat Epidemiol. 1995;9:59–73.[Medline]
4.
McCarthy BJ, Terry J, Rochat RW, Quave S, Tyler CW Jr. The underregistration of neonatal deaths: Georgia 1974–77. Am J Public Health. 1980;70:977–982.
5. MacDorman MF, Atkinson JO. Infant mortality statistics from the 1997 period linked birth/infant death data set. Natl Vital Stat Rep. 1999;47(23):1–23.[Medline]
6. Gaudino JA Jr, Jenkins B, Rochat RW. No fathers' names: a risk factor for infant mortality in the state of Georgia, USA. Soc Sci Med. 1999;48:253–265.
7.
Braveman P, Pearl M, Egerter S, Marchi K, Williams R. Validity of insurance information on California birth certificates. Am J Public Health. 1998;88:813–816.
8.
Buescher PA, Taylor KP, Davis MH, Bowling JM. The quality of the new birth certificate data: a validation study in North Carolina. Am J Public Health. 1993;83:1163–1165.
9. Emery ES, Eaton A, Grether JK, Nelson KB. Assessment of gestational age using birth certificate data compared with medical record data. Paediatr Perinat Epidemiol. 1997;11:313–321.[Medline]
10.
Green DC, Moore JM, Adams MM, Berg CJ, Wilcox LS, McCarthy BJ. Are we underestimating rates of vaginal birth after previous cesarean birth? The validity of delivery methods from birth certificates. Am J Epidemiol. 1998;147:581–586.
11.
Parrish KM, Holt VL, Connell FA, Williams B, LoGerfo JP. Variations in the accuracy of obstetric procedures and diagnoses on birth records in Washington State, 1989. Am J Epidemiol. 1993;138:119–127.
12.
Piper JM, Mitchel EF Jr, Snowden M, Hall C, Adams M, Taylor P. Validation of 1989 Tennessee birth certificates using maternal and newborn hospital records. Am J Epidemiol. 1993;137:758–768.
13.
Watkins ML, Edmonds L, McClearn A, Mullins L, Mulinare J, Khoury M. The surveillance of birth defects: the usefulness of the revised US standard birth certificate. Am J Public Health. 1996;86:731–734.
14.
David RJ. The quality and completeness of birthweight and gestational age data in computerized birth files. Am J Public Health. 1980;70:964–973.
15. Tashiro M. Tape Documentation of Perinatal Record Format: California Birth Cohort, 1996. Sacramento: California Dept of Health Services, Maternal and Child Health Branch; 1999.
16. Wilcox LS, Marks JS. From Data to Action: CDC' Public Health Surveillance for Women, Infants, and Children. Atlanta, Ga: Centers for Disease Control and Prevention; 1993.
This article has been cited by other articles:
|
|
 |
|
  S. Ma Paternal Race/Ethnicity and Birth Outcomes Am J Public Health, December 1, 2008; 98(12): 2285 - 2292. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |