Patterns in Second Stage Labor Care Practices Associated With Genital Tract Injury and Postpartum Hemorrhage During Physiologic Birth: A Latent Mixture Model Analysis

Abstract

INTRODUCTIONGenital tract injury during childbirth contributes to short and long-term problems, including postpartum hemorrhage, incontinence, and pelvic organ prolapse. The purpose of this study was to examine which sets of second stage management techniques employed by midwives attending births in the community setting are associated with genital tract injury and subsequent postpartum hemorrhage.METHODSData from primiparous individuals within the Midwives Alliance of North America (MANA) Stats 2.0 (2004–2009) database were used for this analysis. Latent mixture modeling identified classes (groups) within the sample that are most similar based on 11 different characteristics of second stage management as noted by midwives in their birth notes, including hands-on management techniques during birth, maternal positioning at birth, and water birth.RESULTSThree classes of second stage management techniques best fit this complex dataset. The patterns of techniques used by midwives were only marginally associated with better or worse genital tract outcomes independent of other factors. Two covariables, however, advanced maternal age (OR1.60, 95% CI 1.09–2.34) and births with low fetal heart rate during second stage (OR2.82, 95% CI 1.93–4.10)—were associated with severe genital tract injury. Postpartum hemorrhage was more likely for the two classes where midwives used more hands-on management during second stage, even when considering presence of genital tract injury (OR1.33, 95% CI 1.09–1.63). This study highlights the complex second stage circumstances that interact with management techniques, which together shape or contribute to both genital tissue and hemorrhage outcomes.