Transvaginal ultrasound measurement of posterior cervical angle and cervical length in the prediction of successful induction of labor

Abstract

Induction of labor (IOL) represents a common procedure in everyday obstetric practice: it is used in 30–40% of women. However, IOL may lead to various maternal and fetal hazards. Moreover, failure of IOL is not uncommon (approximately 30%). Therefore, the proper selection of candidates for successful IOL represents a demanding issue in obstetric practice. Aim of the Work: to evaluate the value of the PCA and the cervical length, both measured by transvaginal ultrasonography, compared with the Bishop score in the prediction of the IOL outcome. Patients and Methods: A prospective observational study was conducted 60 patients aged 20–35 years attending labour ward for induction of labour (IOL) with gestational age (37–4+3 weeks), single live fetus in cephalic presentation and low Bishop score < 6 at Ain Shams University Maternity Hospital (labour ward) in the period between March 2019 and September 2019. Results: PCA was a statistically significant factor that favors successful induction of labor (p value=0.012) when compared with CL and Bishop score (P= 0.618 & 0.270) respectively. PCA "≥104.0º cutoff point" had highest diagnostic characteristics in predicting successful induction (sensitivity = 90.6%, specificity = 88.9%, diagnostic accuracy = 90.0%) when compared with CL "≤32.0 mm cutoff point" and Bishop score "≥5.0 cutoff point", (sensitivity = 81.3% & 65.6%, specificity = 88.9% & 83.3%, diagnostic accuracy = 84.0% & 72.0%) respectively. PCA was significantly higher (122.3±14.6 vs. 92.8±13.2), basal CL was significantly lower (28.2±5.5 vs. 37.1±4.9) and BISHOP score was significantly higher (4.7±0.5 vs. 3.8±0.7) among cases with successful induction (P= <0.001). There was no statistical significant difference according to induction outcome regarding neonatal condition; APGAR 1 and 5 scoring levels, NICU admission (P= 0.519, 0.983 & 1.000 consecutively) and maternal complications; fever and diarrhea (p= 0.530 & 0.360 consecutively). Conclusion: In prediction of successful induction of labor, PCA was more significant when compared with CL and Bishop score with the highest diagnostic characteristics at ≥104.0º cutoff point and it was significantly higher among cases with successful induction.