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Date of Award

2-2011

Document Type

Campus Access

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Biostatistics and Epidemiology

First Advisor

Lisa Chasan-Taber

Second Advisor

Penelope S. Pekow

Third Advisor

Elizabeth R. Bertone-Johnson

Subject Categories

Epidemiology | Medicine and Health Sciences | Nursing

Abstract

It has long been traditional for nurse-midwives (CNMs) to keep a log or database of the deliveries they attend. Because CNMs now conduct approximately 400,000 or 10% of all births in the US, these databases are a potentially rich source of research information on the birth outcomes of women cared for by CNMs.

The first study assessed the validity of 3,133 deliveries in the electronic Baystate Midwifery and Women's Health (BMWH) Delivery Database from 2001 to 2008, using the patient's electronic medical record as the 'gold standard'. There have been only four validation studies of nurse-midwifery delivery databases, and these have been limited by small sample sizes, sparse presentation of results and inadequate statistical methodology. Results from these analyses demonstrated excellent overall agreement and a range of agreement by individual variable; agreement among CNM clinicians, by years of CNM clinical experience, and by early versus late study periods was also excellent.

Genital tract trauma is defined as episiotomy and/or genital tract lacerations and is a complication in more than 50% of all vaginal births in the US. Many factors influence the incidence of maternal genital tract trauma.

The second study examined the relationship between provider type, gender and years of clinical experience and the risk of major genital tract trauma among 19,261 spontaneous vaginal births from 2001 to 2008 at Baystate Medical Center. Significantly less major genital tract trauma was associated with later time period, CNM versus physician provider type, and greater than five years of clinical experience. Provider gender did not influence risk of maternal major genital tract trauma.

Finally, we evaluated the relationship between maternal back position, maternal hip flexion, and four derived maternal back and hip flexion positions, and the risk of major genital tract trauma in a cohort of 2,513 vaginal births occurring in 2008 at Baystate Medical Center. Sitting positions were associated with a statistically significant decrease in major genital tract trauma among births attended by CNMs but not physicians. No significant associations were found for hip flexion or derived maternal positions.

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