New approach to the evaluation of perineal measurements to predict the likelihood of the need for an episiotomy.

Abstract

Episiotomy is performed selectively during vaginal delivery. Among the maternal anthropometric factors for episiotomy, the length of the perineal body (pb) and genital hiatus (gh) defined as per the POP-Q system have been studied. The objective of our study was to compare two perineal measurements (defined as per the POP-Q system and the anogenital distance [AGD] concept) to determine which of these can predict the likelihood of an episiotomy being performed. An observational prospective cohort study was designed. Anthropometric data (pb, gh, symphysis-coccyx distance, distance between ischial tuberosities, AGDaf [anus-fourchette], and AGDac [anus-clitoris]), duration of the second stage of labor, and neonatal biometric data were collected from 119 women included in this study. Statistical analysis was performed using Student's t test for unpaired data, Mann-Whitney, and Chi-squared tests. Receiver operating characteristic (ROC) curves were generated to compare AGDaf, AGDac, and "gh + pb" with the presence of episiotomy. A shorter "gh + pb" length and AGDac were risk factors for episiotomy. Compared with AGDac, gh + pb was a slightly better predictor in ROC curve analysis. Furthermore, a longer duration of second-stage labor was evident in the episiotomy group. This study introduces measures of AGD as risk factors for episiotomy. We propose that "gh + pb" length <77mm and AGDac <93mm may predict the likelihood of requiring episiotomy and may be useful for diminishing subjectivity in the decision to perform an episiotomy.