Date of Award

January 2012

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Jessica Illuzzi MD, MS

Subject Area(s)

Obstetrics and gynecology

Abstract

Placenta accreta is a disorder of abnormal placentation that causes significant maternal morbidity and mortality, and whose incidence is rising in the United States. Accreta is thought to be linked closely to endometrial disruption introduced by exposure to uterine surgery; its connection to cesarean delivery is well-established, however, there is a poorer understanding of the contribution made by other forms of uterine surgery, and by relatively subjective indications for which women with placenta accreta may have initially received a cesarean delivery. The aims of the study were to quantify the rate of placenta accreta at YNHH, the rate of exposure to various uterine surgeries prior to the accreta pregnancy, and the rate of subjective indication for primary cesarean delivery amongst all patients with placenta accreta from 1995-2011. Among the 72,845 births during the study period, 249 cases of placenta accreta were identified via query of pathology records, including 122 focal accreta, 63 accreta vera, 23 increta and 14 percreta.

Twenty-seven cases were excluded due to lost chart, multiple accreta in a single patient, and absence of baseline birth data for Jan 1995 - June 1996; a total of 100 cases of non-focal accreta were included in the final analysis. Non-focal accreta is increasing over the study period; the rate was 1.4 cases per 1,000 births; it increased on average 12% per 3-year period over the course of the study (95% CI -1.6% to 28.5%). Among all births, women with placenta accreta and a prior index cesarean delivery increased significantly over the study period, with a mean increase of 21.9% per 3-year period (95% CI1.4% to 46.6%), while those with placenta accreta and other index uterine surgery increased by 71.1% per 3-year period (95% CI 10.4% to 165%). Over this 15 year period, the cumulative increase in risk of having placenta accreta in the setting of prior cesarean delivery was 2.69 (95% CI 1.07 - 6.8) while the cumulative increase in risk for having placenta accreta in the setting of prior other uterine surgery was 14.66 (95% CI 1.64 - 131). There was no significant difference in rate of placenta accreta with prior index cesarean delivery for subjective or objective indication. Placenta accreta in the setting of prior uterine surgery is increasing over time. Larger studies are needed to further elucidate the increasing role of prior uterine surgery on the development of placenta accreta in the population.

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