To assess the association of cervical effacement with the rate of intrapartum cervical change among nulliparous women.
We conducted a secondary analysis of a prospective trial of intrapartum fetal pulse oximetry. For women who had vaginal deliveries, interval-censored regression was used to estimate the time to dilate at 1-cm intervals. For each given centimeter of progressive cervical dilation, women were divided into those who had achieved 100% cervical effacement and those who had not. The analysis was performed separately for women in spontaneous labor and those who were given oxytocin.
A total of 3,902 women were included in this analysis, 1,466 (38%) who underwent labor induction, 1,948 (50%) who underwent labor augmentation (combined for the analysis), and 488 (13%) who labored spontaneously. For women in spontaneous labor, the time to dilate 1 cm was shorter for those who were 100% effaced starting at 4 cm of cervical dilation (P=.01 to <.001). For women who received oxytocin, the time to dilate 1 cm was shorter for those who were 100% effaced throughout labor (P<.001).
The rate of cervical dilation among nulliparous women is associated with not only the degree of cervical dilation, but also with cervical effacement.
ClinicalTrials.gov, www.clinicaltrials.gov, NCT00098709.
Achievement of 100% cervical effacement is associated with a shorter median time of dilation among nulliparous women.
Departments of Obstetrics and Gynecology, Stanford University, Stanford, California, the University of Texas Southwestern Medical Center, Dallas, Texas, the University of Alabama at Birmingham, Birmingham, Alabama, the University of Utah Health Sciences Center, Salt Lake City, Utah, the University of Texas Health Science Center at Houston–Children's Memorial Hermann Hospital, Houston, Texas, the University of Pittsburgh, Pittsburgh, Pennsylvania, Northwestern University, Chicago, Illinois, Wayne State University, Detroit, Michigan, Drexel University, Philadelphia, Pennsylvania, Brown University, Providence, Rhode Island, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, Columbia University, New York, New York, and The Ohio State University, Columbus, 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: Elizabeth S. Langen, MD, Obstetrics and Gynecology, Floor 9, Room 109 VVWH, 1540 W Hospital Drive, SPC 4264, Ann Arbor, MI 48109-4264; e-mail: email@example.com.
Supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (HD21410, HD27860, HD27869, HD27915, HD27917, HD34116, HD34136, HD34208, HD40485, HD40500, HD40512, HD40544, M01 RR00080 (NCRR); HD40545, HD40560, and HD36801).
Comments and views of the authors do not necessarily represent views of the NICHD.
Financial Disclosure The authors did not report any potential conflicts of interest.
Presented at the Society for Maternal-Fetal Medicine annual meeting, February 11–16, 2013, San Francisco, California.
* For a list of other members of the NICHD MFMU Network, see Appendix 1 online at http://links.lww.com/AOG/A781.
The authors thank Allison Todd, MSN, RN, for protocol development and coordination between clinical research centers; Elizabeth Thom, PhD, for protocol development, data management, and statistical analysis; and Kenneth J. Leveno, MD, and Catherine Y. Spong, MD, for protocol development and oversight.
Dr. Rouse, Associate Editor of Obstetrics & Gynecology, was not involved in the review or decision to publish this article.