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APHA Scientific Session and Event Listing

Recorded presentation

Heather A. Davidson, PhD, Department of Psychology and Human Development, Vanderbilt University, 230 Appleton Place, Nashville, TN 37203, 615-414-3748, hdavidson1@yahoo.com

Freestanding birth centers (FBCs) offer prenatal and childbirth services outside hospital settings where nurse-midwives are the primary providers for women with low-risk pregnancies. Although previous research provides evidence supporting the safety of FBCs, critiques of methodological procedures question the validity of these claims because of potential effects of hidden bias common in observational studies. The purpose of this study is to assess safety by testing whether FBCs, compared to hospital-based services, produce comparable pregnancy outcomes. Data are obtained through Tennessee birth and death certificates from 1990-2002. Outcomes from FBCs are compared with two hospital groups: women with low-risk pregnancies, and women with midwife-attended hospital births. For the midwife-attended comparison, pregnancy outcomes are controlled for pre-existing risk profiles by using logistic regression and propensity score analysis. Results find that FBCs are significantly less likely than hospital groups to have occurrence of LBW, small for gestational age, preterm birth, fetal distress, and maternal complications during labor. Incidences of infant abnormal conditions and low Apgar scores are statistically equivalent in both groups. Giving birth to an infant who is large for gestational age occurs more frequently in the FBC group than either hospital group; the outcome is only statistically significant when compared to the midwife-attended hospital group. Limiting comparison groups to low-risk pregnancy and midwife-attended hospital births and using propensity scores to balance pre-existing risk factors across groups contribute to minimizing bias found in observational studies. Using these techniques provides stronger evidence that FBCs can be a relatively safe option for eligible women.

Learning Objectives: At the conclusion of the session, the participant (learner) in this session will be able to

• Integrate results about the safety of freestanding birth centers into current and future maternal health policy discussions.
• Recognize propensity score analysis as a methodological technique for comparing maternal health services.
• Discuss techniques that help minimize hidden bias found in observational studies.

Keywords: Pregnancy Outcomes, Evidence Based Practice

Presenting author's disclosure statement:

Any relevant financial relationships? No

Recorded presentation