Am J Perinatol 2016; 33(06): 590-599
DOI: 10.1055/s-0035-1570380
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Association between Hospital Birth Volume and Maternal Morbidity among Low-Risk Pregnancies in Rural, Urban, and Teaching Hospitals in the United States

Katy B. Kozhimannil
1  Division of Health Policy and Management, University of Minnesota School of Public Health, Minneapolis, Minnesota
,
Viengneesee Thao
1  Division of Health Policy and Management, University of Minnesota School of Public Health, Minneapolis, Minnesota
,
Peiyin Hung
1  Division of Health Policy and Management, University of Minnesota School of Public Health, Minneapolis, Minnesota
,
Ellen Tilden
2  Department of Nurse-Midwifery, Oregon Health and Sciences University School of Nursing, Portland, Oregon
,
Aaron B. Caughey
3  Department of Obstetrics and Gynecology, Oregon Health and Sciences University School of Medicine, Portland, Oregon
,
Jonathan M. Snowden
3  Department of Obstetrics and Gynecology, Oregon Health and Sciences University School of Medicine, Portland, Oregon
› Author Affiliations
Further Information

Publication History

03 November 2015

10 November 2015

Publication Date:
05 January 2016 (online)

Abstract

Objectives This study aims to examine the relationship between hospital birth volume and multiple maternal morbidities among low-risk pregnancies in rural hospitals, urban non-teaching hospitals, and urban teaching hospitals, using a representative sample of U.S. hospitals.

Study Design Using the 2011 Nationwide Inpatient Sample from 607 hospitals, we identified 508,146 obstetric deliveries meeting low-risk criteria and compared outcomes across hospital volume categories. Outcomes include postpartum hemorrhage (PPH), chorioamnionitis, endometritis, blood transfusion, severe perineal laceration, and wound infection.

Results Hospital birth volume was more consistently related to PPH than to other maternal outcomes. Lowest-volume rural (< 200 births) and non-teaching (< 650 births) hospitals had 80% higher odds (adjusted odds ratio [AOR] = 1.80; 95% CI = 1.56–2.08) and 39% higher odds (AOR = 1.39; 95% CI = 1.26–1.53) of PPH respectively, than those in corresponding high-volume hospitals. However, in urban teaching hospitals, delivering in a lower-volume hospital was associated with 14% lower odds of PPH (AOR = 0.86; 95% CI = 0.80–0.93). Deliveries in rural hospitals had 31% higher odds of PPH than urban teaching hospitals (AOR = 1.31; 95% CI = 1.13–1.53).

Conclusions Low birth volume was a risk factor for PPH in both rural and urban non-teaching hospitals, but not in urban teaching hospitals, where higher volume was associated with greater odds of PPH.