OBJECTIVE: Women with a prior myomectomy or prior classical cesarean delivery often have early delivery by cesarean because of concern for uterine rupture. Although theoretically at increased risk for placenta accreta, this risk has not been well-quantified. Our objective was to estimate and compare the risks of uterine rupture and placenta accreta in women with prior uterine surgery.
METHODS: Women with prior myomectomy or prior classical cesarean delivery were compared with women with a prior low-segment transverse cesarean delivery to estimate rates of both uterine rupture and placenta accreta.
RESULTS: One hundred seventy-six women with a prior myomectomy, 455 with a prior classical cesarean delivery, and 13,273 women with a prior low-segment transverse cesarean delivery were evaluated. Mean gestational age at delivery differed by group (P<.001), prior myomectomy (37.3 weeks), prior classical cesarean delivery (35.8 weeks), and low-segment transverse cesarean delivery (38.6 weeks). The frequency of uterine rupture in the prior myomectomy group (P-MMX group) was 0% (95% confidence interval [CI] 0–1.98%). The frequency of uterine rupture in the low-segment transverse cesarean delivery group (LTC group) (0.41%) was not statistically different from the risk in the P-MMX group (P>.99) or in the prior classical cesarean delivery group (PC group) (0.88%; P=.13). Placenta accreta occurred in 0% (95% CI 0–1.98%) of the P-MMX group compared with 0.19% in the LTC group (P>.99) and 0.88% in the PC group (P=.01 relative to the LTC group). The adjusted odds ratio for the PC group (relative to LTC group) was 3.23 (95% CI 1.11–9.39) for uterine rupture and 2.09 (95% CI 0.69–6.33) for accreta. The frequency of accreta for those with previa was 11.1% for the PC group and 13.6% for the LTC group (P>.99).
CONCLUSION: A prior myomectomy is not associated with higher risks of either uterine rupture or placenta accreta. The absolute risks of uterine rupture and accreta after prior myomectomy are low.
Prior myomectomy, under existing care standards, is not associated with higher risks of either uterine rupture or placenta accreta compared with prior cesarean delivery.
Departments of Obstetrics and Gynecology, Columbia University, New York, New York, Ohio State University, Columbus, Ohio, University of Alabama at Birmingham, Birmingham, Alabama, University of Utah, Salt Lake City, Utah, University of Pittsburgh, Pittsburgh, Pennsylvania, Wake Forest University Health Sciences, Winston-Salem, North Carolina, Thomas Jefferson University, Philadelphia, Pennsylvania, Wayne State University, Detroit, Michigan, Brown University, Providence, Rhode Island, Northwestern University, Chicago, Illinois, University of Miami, Miami, Florida, University of Tennessee, Memphis, Tennessee, University of North Carolina, Chapel Hill, North Carolina, University of Texas Health Science Center at Houston, Houston, Texas, and Case Western Reserve University-MetroHealth Medical Center, Cleveland, Ohio; The George Washington University Biostatistics Center, Washington, DC; and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland.
Corresponding author: Cynthia Gyamfi-Bannerman, MD, Associate Clinical Professor, Columbia University Medical Center, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, 622 West 168th Street, PH-16, New York, NY 10032; e-mail: email@example.com.
The project described was supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (grants HD21410, HD21414, HD27860, HD27861, HD27869, HD27905, HD27915, HD27917, HD34116, HD34122, HD34136, HD34208, HD34210, HD40500, HD40485, HD40544, HD40545, HD40560, HD40512, and HD36801), and its contents are solely the responsibility of the authors and do not necessarily represent the official view of Eunice Kennedy Shriver National Institute of Child Health and Human Development or the National Institutes of Health.
Financial Disclosure The authors did not report any potential conflicts of interest.
Presented at the Society for Gynecologic Investigation, March 24--27, 2010, Orlando, Florida.
* For a list of other members of the NICHD MFMU, see the Appendix online at http://links.lww.com/AOG/A331.
The authors thank Francee Johnson, RN, BSN, for protocol development and coordination between clinical research centers; Elizabeth Thom, PhD, for protocol and data management and statistical analysis; and Ronald J. Wapner, MD, and John C. Hauth, MD, for protocol development and oversight.
Dr. Spong, Associate Editor of Obstetrics & Gynecology, was not involved in the review of this article or the decision to publish this article.