Cesarean Delivery Rate in Nulliparous Women in the Second Stage of Labor When Using Zhang Compared With Friedman Labor Curves

Abstract

OBJECTIVE: To estimate the cesarean delivery rate in the second stage of labor in nulliparous women when using the Zhang compared with the Friedman labor curve by performing a systematic review and meta-analysis. DATA SOURCES: We explored MEDLINE, EMBASE, Web of Science, CINAHL (Cumulative Index to Nursing and Allied Health Literature), ClinicalTrials.gov, and Cochrane Central Register of Controlled Trials for studies comparing the cesarean delivery rate in the second stage of labor in nulliparous women when using the Zhang compared with the Friedman labor curve. METHODS OF STUDY SELECTION: Two reviewers separately ascertained studies, obtained data, and gauged study quality. The cesarean delivery rate was compared, and odds ratios (ORs) with 95% CIs were estimated. TABULATION, INTEGRATION, AND RESULTS: Five retrospective cohort studies and two randomized controlled trials were identified with 20,165 nulliparous women (10,861 with the Zhang labor curve vs 9,304 with the Freidman labor curve). Studies evaluated women with delivery from June 2010 to May 2017. Two studies were from the United States; two were from Israel; and one each was from China, France, and Norway. The median point prevalence of cesarean delivery in the second stage was 4.0% (95% CI 2.1–14.5%) in cases managed with the Zhang labor curve compared with 5.6% (95% CI 1.8–28.6%) in cases managed with the Friedman labor curves. The overall cesarean delivery rate in the second stage of labor was similar when the Zhang labor curve compared with the Friedman labor curve was used (pooled OR 0.86, 95% CI 0.47–1.57, I 2=93%). When the two randomized controlled trials were excluded, the results of the cohort studies continued to demonstrate that the overall cesarean delivery rate in the second stage of labor was similar (pooled OR 0.84, 95% CI 0.42–1.69, I 2=92%). CONCLUSION: Nulliparous women have similar cesarean delivery rates in the second stage of labor when either the Zhang or Friedman labor curve is used. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42022346425.