Fetal head–perineum distance measured by transperineal ultrasound imaging as a predictive factor for successful induction of labor

Abstract

ObjectiveThe aim of the study was to evaluate fetal head-perineum distance measured by transperineal ultrasound imaging as a predictive factor for successful induction of labor. Patients and methodsIn all, 100 women scheduled for induction of labor with the head engaged were examined by both transvaginal and transperineal ultrasound together with the Bishop score. Follow-up was performed and outcome was compared. Receiver operating characteristic (ROC) curve was performed to estimate the best cutoff value. ResultsAreas under the ROC curve for prediction of vaginal delivery were 78% [95% confidence interval (CI), 61-95%] for fetal head-perineum distance (P = 0.04), 73% (95% CI, 61-94%) for cervical length (P = 0.05), 42% (95% CI, 26-60%) for cervical width (P = 0.044), and 59% (95% CI, 34-85%) for Bishop score (P = 0.046). The ROC curves indicated that fetal head-perineum distance of 8.6 cm or less and cervical length of 3.3 cm or less were the best cutoff levels for predicting the mode of delivery. Conclusion Fetal head-perineum distance measured by transperineal ultrasound imaging is a good predictive factor for successful induction of labor in pregnant women with engaged head.

Transvaginal ultrasound parameters to evaluate cervical favorability and predict the outcome of induction of labor

“…Other parameters were measured by two clinicians and the average value would be calculated. Each indicator was measured according to the recommended standard method in previous studies 6–9,15,19 …”

“…Each indicator was measured according to the recommended standard method in previous studies. [6][7][8][9]15,19 The latent phase was determined from the rupture of membranes and the onset of regular uterine contractions (more than three times in 10 min) induced by oxytocin to cervical dilatation of 5 cm. 20 The duration of the latent phase and the duration of vaginal delivery were recorded.…”

“…For objective examination, transvaginal ultrasound (TVU) parameters were used as substitutes for BS for predicting the outcome of IOL as early as 1991 3 . Subsequently, several TVU parameters, consisting of CL, the dilatation of the internal cervical os, fetal head–perineum distance (FHPD), and posterior cervical angle (PCA), were evaluated in some studies, albeit the predictive value of these parameters remains debatable 4–9 . Some studies have indicated that CL could be used as an independent significant indicator in predicting the outcome of IOL with a better predictive value compared with BS, 4,5 while another piece of research showed that CL and BS have equal prediction of successful IOL 6 .…”