Fetal deaths in the United States, 1997 vs 1991

doi:10.1016/j.ajog.2004.12.002

American Journal of Obstetrics and Gynecology

Volume 193, Issue 2, August 2005, Pages 489-495

https://doi.org/10.1016/j.ajog.2004.12.002 Get rights and content

Objective

The purpose of this study was to examine the temporal change in fetal death risk in the US from 1991 to 1997, and to assess the extent to which changes in registration practices and labor induction have contributed to that change.

Study design

This was a cohort study of all singleton pregnancies 20 to 43 weeks of gestation in 1991 and 1997 in the US.

Results

From 1991 to 1997, the overall fetal death rate fell from 77.6 to 67.8 per 10,000 total births. However, fetal deaths at 20 to 22 weeks as a proportion of total births increased from 14.5 to 16.9 per 10,000. In a Cox regression analysis, the crude period effect (1997 vs 1991) at 40 to 43 weeks was 0.87 (95% CI 0.80-0.94), and remained virtually unchanged (HR 0.88, 95% CI 0.81-0.96) after adjustment for maternal sociodemographic, medical, and lifestyle risk factors. In ecologic (Poisson regression) analysis based on states as the unit of analysis, the crude period effect in non-Hispanic whites (RR 0.79, 95% CI 0.74-0.84) disappeared (RR 0.98, 95% CI 0.82-1.16) after adjusting for induction of labor. The effect of induction in blacks was limited to 42 to 43 weeks in those at high risk.

Conclusion

Increased registration is probably responsible for an increase in fetal death risk at 20 to 22 weeks of gestation, whereas the increasing trend toward routine labor induction at and after term appears to have reduced the risk of fetal death, especially among whites.

Section snippets

Material and methods

Our study is based on the US live birth and fetal death files for the years 1991 and 1997.⁸ No data were available on obstetric procedures (ie, labor induction) before the 1989 revision of US vital statistic files, and were incomplete until 1991. The 1997 file was the most recent available when the study was initiated. Because multiple gestations are associated with a high risk of fetal death, we restricted our analyses to singleton births. All singleton fetal deaths ≥20 weeks of gestation are

Results

For both whites and blacks, the fetal death risk in 1991 and 1997 from 20 to 43 weeks is shown for the 50 states (plus DC) in Figure 1. From 1991 to 1997, the fetal death risk for whites and blacks combined in the 50 states and DC increased by 18% at 20 to 22 weeks of gestation from 10.6 to 12.5 per 10,000 ongoing pregnancies (RR 1.18, 95% CI 1.13-1.23), whereas from 40 to 43 weeks, it decreased by 22% from 12.2 to 9.5 per 10,000 ongoing pregnancies (RR 0.78, 95% CI 0.73-0.83). For whites, the

Comment

Fetal deaths at 20 to 22 weeks increased relative to total births (at all GAs) between 1991 and 1997, although no similar increase was found at other early GA categories (23-25 or 26-28 weeks). A similar increase in the proportion of fetal deaths <500 g (relative to total births) was documented in the state of Alabama from 1974 to 1994, and in Canada from 1985 to 1995 (note: birth weight of 500 g approximately corresponds to a GA of 22 weeks), but was not observed in other low-birth-weight

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Cited by (34)

Racial and Ethnic Disparities in United States: Stillbirth Rates: Trends, Risk Factors, and Research Needs
2011, Seminars in Perinatology
Citation Excerpt :
It is unclear how much each of these factors contributes to racial disparity on small-for-gestational-age fetuses and subsequently stillbirth. The increasing trend toward inducing labor for term pregnancies has been credited with a 21% improvement in stillbirth risk from 1991 to 1997 among non-Hispanic whites.7 However, among non-Hispanic blacks, trends in increased labor induction affected stillbirth risks only for high-risk women with gestational ages of 42-43 weeks.7
As with most adverse health outcomes, there has been long standing and persistent racial and ethnic disparity for stillbirth in the United States. In 2005, the stillbirth rate (fetal deaths ≥20 weeks' gestation per 1000 fetal deaths and live births) for non-Hispanic blacks was 11.13 compared with 4.79 for non-Hispanic whites. Rates were intermediate for American Indian or Alaska Natives (6.17) and Hispanics (5.44). There is racial disparity for both early (<28 weeks' gestation) and late stillbirths. We review available data regarding risk factors for stillbirth with a focus on those factors that are more prevalent in certain racial/ethnic groups and those factors that appear to have a more profound effect in certain racial/ethnic groups. Although many factors, including genetics, environment, stress, social issues, access to and quality of medical care and behavior, contribute to racial disparity in stillbirth, the reasons for the disparity remain unclear. Knowledge gaps and recommendations for further research and interventions intended to reduce racial disparity in stillbirth are highlighted.
The study of stillbirth
2009, American Journal of Obstetrics and Gynecology
Racial disparities in stillbirth risk across gestation in the United States
2009, American Journal of Obstetrics and Gynecology
Citation Excerpt :
This study examines the hazard of stillbirth using ongoing pregnancies as the comparison group, which provides a clinically relevant estimate of stillbirth risk at intervals in gestation.6 The risk of stillbirth is greatest at the beginning (20–23 weeks) and at the end (39–41 weeks) of gestation regardless of race/ethnicity, as has been previously described.7 Non-Hispanic black women have a 2.2-fold increased risk of stillbirth compared with non-Hispanic white women.
We sought to determine factors associated with racial disparities in stillbirth risk.
Stillbirth hazard was analyzed using 5,138,122 singleton gestations from the National Center of Health Statistics perinatal mortality and birth files, 2001–2002.
Black women have a 2.2-fold increased risk of stillbirth compared with white women. The black/white disparity in stillbirth hazard at 20–23 weeks is 2.75, decreasing to 1.57 at 39–40 weeks. Higher education reduced the hazard for whites more than for blacks and Hispanics. Medical, pregnancy, and labor complications accounted for 30% of the hazard in blacks and 20% in whites and Hispanics. Congenital anomalies and small for gestational age contributed more to preterm stillbirth risk among whites than blacks. Pregnancy and labor conditions contributed more to preterm stillbirth risk among blacks than whites.
The excess stillbirth risk for blacks was greatest at preterm gestations, and factors contributing to stillbirth risk vary by race and gestational age.
From Paradox to Disparity: Trends in Neonatal Death in Very Low Birth Weight non-Hispanic Black and White Infants, 1989-2004
2009, Journal of Pediatrics
To examine temporal trends in race-specific neonatal death in California to determine whether the overall decline in mortality attenuated the paradoxical survival advantage of very low birth weight (VLBW; birth weight < 1500 g) non-Hispanic black infants relative to VLBW non-Hispanic white infants.
The data set comprised the California birth cohort file on non-Hispanic black and non-Hispanic white VLBW neonatal mortality for 1989-2004. Logistic regression methods were used to control for potentially confounding maternal characteristics.
In 1989 and 1990, non-Hispanic black VLBW infants demonstrated a paradox of lower neonatal mortality (adjusted odds ratio [aOR] = 0.84; 95% confidence interval [CI] = 0.75-0.94). This survival advantage disappeared after 1991, however. In 2003 and 2004, the incidence of neonatal mortality increased in non-Hispanic black VLBW infants but decreased in non-Hispanic white VLBW infants, resulting in a racial disparity (aOR = 1.34; 95% CI = 1.14-1.56).
An initial survival paradox transformed into a disparity. The magnitude of this non-Hispanic black/non-Hispanic white VLBW disparity rose to its highest levels in the last 2 years of the study period. Moreover, the steady mortality increase in VLBW non-Hispanic black VLBW infants since 2001 reversed the secular decline in neonatal mortality in this population. Our findings underscore the need to augment strategies to improve the health trajectory of gestation in non-Hispanic black women.
Variations in Mortality and Morbidity by Gestational Age among Infants Born at Term
2009, Journal of Pediatrics
To examine the risks of infant death and neonatal morbidity by week of gestation at term.
National U.S. birth cohort study on the basis of singleton live births in 1995-2001 at 37 to 41 completed weeks gestational age (GA), with exclusion of congenital anomalies. Main outcomes included neonatal, postneonatal, and cause-specific infant death; low-Apgar score at 5 minutes; receipt of neonatal mechanical ventilation ≥30 minutes; neonatal seizures; birth injury; and meconium aspiration syndrome. To reduce confounding by indication, we carried out a secondary analysis restricted to low-risk deliveries.
In non-Hispanic white women, the mortality rate decreased with increasing GA from 37 to 39 weeks, remained stable from 39 to 40 weeks, and then (for neonatal death) increased at 41 weeks. Rates of low 5-minute Apgar score and mechanical ventilation showed a U-shaped relation across term GAs, and rates of meconium aspiration syndrome and birth injury rose with increasing GA. Results were similar among infants born to low-risk mothers and in non-Hispanic black women.
Term infants show considerable heterogeneity across gestational age in neonatal and late infant outcomes, even when born to mothers at low risk. Recent trends toward earlier labor induction may have adverse health impacts.
New Indications for Antepartum Testing: Making the Case for Antepartum Surveillance or Timed Delivery for Women of Advanced Maternal Age
2008, Seminars in Perinatology
Citation Excerpt :
Obvious differences in neonatal and stillbirth rates may be due to many factors including access to obstetrical care, quality of care, stress, diet, and biological factors. Black women in the US, for example, experience a two-fold risk of stillbirth when compared with whites with a higher rate of stillbirth both early in gestation and late in gestation.4 There are no trials specifically addressing the potential role of antepartum testing and timed delivery in black women, although Yuan and colleagues using US data compared induction and stillbirth rates in 1997 versus 1991.4
Maternal age is an independent risk factor for stillbirth; a moderate number of these occur in normally formed babies near term. For a woman 40 years of age or older giving birth, her risk of having a chromosomal anomaly is 1/66. What is not appreciated is that even without medical risk factors, her risk of having a stillbirth after 37 weeks of gestation is 1/116. This article reviews the risks and benefits of the strategy of antepartum testing and timed delivery and discusses the limitations of the available data in this field.

View all citing articles on Scopus

: Drs Kramer, Platt, and Joseph are career investigators of the Canadian Institutes of Health Research, and Dr Joseph is also a Clinical Research Scholar of the Dalhousie University Faculty of Medicine.

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General Obstetrics and Gynecology: ObstetricsFetal deaths in the United States, 1997 vs 1991

Objective

Study design

Results

Conclusion

Section snippets

Material and methods

Results

Comment

Obstet Gynecol

Lancet

Obstet Gynecol

National Vital Statistics Reports

Fetal deaths

The changing pattern of fetal death, 1961-1988

Obstet Gynecol

The changing panorama of late fetal death in Sweden between 1984 and 1991

Acta Obstet Gynecol Scand

Fetal deaths in Alabama, 1974-1983: a birth weight-specific analysis

Obstet Gynecol

Instruction manual, computer edits for natality data, part 12

Trends in preterm birth and neonatal mortality among blacks and whites in the United States from 1989 to 1997

Am J Epidemiol

General Obstetrics and Gynecology: Obstetrics
Fetal deaths in the United States, 1997 vs 1991