Sidi Kasbaoui1, François Séverac2, Germain Aïssi1, Adrien Gaudineau1, Lise Lecointre1, Chérif Akladios1, Romain Favre1, Bruno Langer1, Nicolas Sananès3. 1. Department of Obstetrics and Gynecology, Strasbourg University Hospital, Strasbourg, France. 2. Department of Public Health, Strasbourg University Hospital, Strasbourg, France. 3. Department of Obstetrics and Gynecology, Strasbourg University Hospital, Strasbourg, France; Unité Mixte de Recherche 1121 Inserm, Biomaterials et Bioengineering, Strasbourg, France. Electronic address: nicolas.sananes@chru-strasbourg.fr.
Abstract
BACKGROUND: Clinical assessment of fetal head station is difficult and subjective; it is mandatory before attempting operative vaginal delivery. OBJECTIVE: The principal objective of our study was to assess whether measurement of the perineum-to-skull ultrasound distance was predictive of a difficult operative vaginal delivery. Secondary objectives included evaluation of the interobserver reproducibility of perineum-to-skull ultrasound distance and comparison of this measurement and digital examination in predicting a difficult operative delivery. STUDY DESIGN: This was a prospective cohort study including all cases of operative vaginal deliveries in singleton pregnancies in cephalic presentation >34 weeks' gestation, from 2012 through 2015. All data were entered prospectively in a medical record system specially devised to meet the requirements of this study. RESULTS: Of the 659 patients in whom perineum-to-skull ultrasound distance was measured prior to operative vaginal delivery, 120 (18%) met the composite criterion for a difficult extraction. Perineum-to-skull ultrasound distance measurement of ≥40 mm was significantly associated with the occurrence of a difficult extraction based on the composite criterion, after adjustment for parity, presentation type, and fetal macrosomia (odds ratio, 2.38; 95% confidence interval, 1.51-3.74; P = .0002). The intraclass correlation coefficient between the perineum-to-skull ultrasound distance measured by the first operator and that measured by the second operator was 0.96 (95% confidence interval, 0.95-0.97; P < .0001). Based on the receiver operating characteristic curve analyses, perineum-to-skull ultrasound distance was a more accurate predictor of difficult operative delivery than digital vaginal examination (P = .036). CONCLUSION: Measurement of the perineum-fetal skull ultrasound distance is a reproducible and predictive index of the difficulty of instrumental extraction. Ultrasound is a useful supplementary tool to the usual clinical findings.
BACKGROUND: Clinical assessment of fetal head station is difficult and subjective; it is mandatory before attempting operative vaginal delivery. OBJECTIVE: The principal objective of our study was to assess whether measurement of the perineum-to-skull ultrasound distance was predictive of a difficult operative vaginal delivery. Secondary objectives included evaluation of the interobserver reproducibility of perineum-to-skull ultrasound distance and comparison of this measurement and digital examination in predicting a difficult operative delivery. STUDY DESIGN: This was a prospective cohort study including all cases of operative vaginal deliveries in singleton pregnancies in cephalic presentation >34 weeks' gestation, from 2012 through 2015. All data were entered prospectively in a medical record system specially devised to meet the requirements of this study. RESULTS: Of the 659 patients in whom perineum-to-skull ultrasound distance was measured prior to operative vaginal delivery, 120 (18%) met the composite criterion for a difficult extraction. Perineum-to-skull ultrasound distance measurement of ≥40 mm was significantly associated with the occurrence of a difficult extraction based on the composite criterion, after adjustment for parity, presentation type, and fetal macrosomia (odds ratio, 2.38; 95% confidence interval, 1.51-3.74; P = .0002). The intraclass correlation coefficient between the perineum-to-skull ultrasound distance measured by the first operator and that measured by the second operator was 0.96 (95% confidence interval, 0.95-0.97; P < .0001). Based on the receiver operating characteristic curve analyses, perineum-to-skull ultrasound distance was a more accurate predictor of difficult operative delivery than digital vaginal examination (P = .036). CONCLUSION: Measurement of the perineum-fetal skull ultrasound distance is a reproducible and predictive index of the difficulty of instrumental extraction. Ultrasound is a useful supplementary tool to the usual clinical findings.