Racial Disparities in Term Induction of Labor Rates in Illinois

Racial/Ethnic Differences in Labor Induction in a Contemporary US Cohort: A Retrospective Cohort Study

OBJECTIVE

To examine labor induction by race/ethnicity and factors associated with disparity in induction.

STUDY DESIGN

This is a retrospective cohort study of 143,634 women eligible for induction ≥24 weeks' gestation from 12 clinical centers (2002-2008). Rates of labor induction for each racial/ethnic group were calculated and stratified by gestational age intervals: early preterm (240/7-336/7), late preterm (340/7-366/7), and term (370/7-416/7 weeks). Multivariable logistic regression examined the association between maternal race/ethnicity and induction controlling for maternal characteristics and pregnancy complications. The primary outcome was rate of induction by race/ethnicity. Inductions that were indicated, non-medically indicated, or without recorded indication were also compared.

RESULTS

Non-Hispanic black (NHB) women had the highest percentage rate of induction, 44.6% (p < 0.001). After adjustment, all racial/ethnic groups had lower odds of induction compared with non-Hispanic white (NHW) women. At term, NHW women had the highest percentage rate (45.4%) of non-medically indicated or induction with no indication (p < 0.001).

CONCLUSION

Compared with other racial/ethnic groups, NHW women were more likely to undergo non-medically indicated induction at term. As labor induction may avoid the occurrence of stillbirth, whether this finding explains part of the increased risk of stillbirth for NHB women at term merits further research.

National trends and racial differences in late preterm induction

OBJECTIVE

The objective of the study was to determine the trends and racial differences in late preterm induction (LPI) of labor in the United States.

STUDY DESIGN

Data from the National Vital Statistics System were used to identify women eligible for induction between 34 and 42 weeks' gestation from 1991 to 2006. Annual LPI rates were calculated, and maternal race/ethnicity was classified into 4 groups. Changes in the frequency and odds of LPI, stratified by race/ethnicity, were assessed using logistic regression.

RESULTS

Among the 42.0 million eligible women, LPI rates increased from 0.46% to 1.37% (P < .01) over 16 years. LPI rates were highest for black women (P < .01) each year, and after adjusting for confounding factors, the odds of LPI were highest (P < .01) and rose most rapidly (P < .01) for black women (non-Hispanic white: odds ratio [OR], 1 [referent]; Hispanic white: OR, 0.76; black: OR, 1.31; other: OR, 0.81; P < .01).

CONCLUSION

LPI rates were persistently highest and rose most rapidly for black women.

Trends in induction of labor at early-term gestation

OBJECTIVE

To determine the trends and racial differences in early-term induction of labor in the United States.

STUDY DESIGN

Data from the National Center for Health Statistics were used to identify women eligible for induction between 37-42 weeks' gestation in the United States from 1991-2006. Annual early-term induction rates were calculated, and maternal race/ethnicity was classified into 4 groups. The change in frequency and odds of early-term induction stratified by race/ethnicity over time was assessed.

RESULTS

Among 39.2 million eligible women, early-term induction rates increased from 2.0% to 8.0% (P < .01) over 16 years. Cross-sectional and annual early-term induction rates were highest for non-Hispanic white women during the study period (P < .01). After adjusting for confounding factors, the odds of any early-term induction were highest (P < .01) and rose most rapidly (P < .01) among non-Hispanic white women compared with women from other racial/ethnic groups.

CONCLUSION

In the United States, early-term induction rates rose significantly and were highest among non-Hispanic white women.

Racial disparities in stillbirth risk across gestation in the United States

OBJECTIVE

We sought to determine factors associated with racial disparities in stillbirth risk.

STUDY DESIGN

Stillbirth hazard was analyzed using 5,138,122 singleton gestations from the National Center of Health Statistics perinatal mortality and birth files, 2001-2002.

RESULTS

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.

CONCLUSION

The excess stillbirth risk for blacks was greatest at preterm gestations, and factors contributing to stillbirth risk vary by race and gestational age.