Prediction of labor outcome by measuring the angle of progression using two dimensional trans-perineal Ultrasound: A prospective cohort study

Background: Failure of descent due to fetal malposition is one of the most common indications for performing surgical deliveries. It has recently been suggested that trans-perineal intra-partum ultrasonography may be useful in assessing fetal head engagement, position and station as well as it’s reliable, cheap, painless and effective tool. Measuring the ‘angle of progression’ could assist in the obstetrician’s decision regarding mode of delivery. Objectives: The primary outcome is to use the AOP to develop a predictive model for the probability of successful vaginal delivery. Secondary outcomes including assessment of possibly successful VBAC in previous one CS women. Methods: We recruited 500 women in labor. For each woman, a (TPU) was performed to measure the AOP in late first and second stages of labor. We compared AOP between women who delivered fetuses through vaginal route to those who delivered by CS. Results: Through 467 women included in the study, AOP was significantly Higher in spontaneous vaginal delivery group (with cut off 123°±8.5°) as compared with women delivered by vacuum or by CS (113°±10.5°) (P=0.003). The VBAC as another secodary outcome seems to be insignificant. Conclusions: TPU is safe, non-invasive and easily preformed technique which is useful to predict labor outcomes.

Angle of progression with trans-perineal ultrasound and delivery type in labor’s second stage; a cross-sectional study in Isfahan, Iran

Introduction: Numerous studies have shown that clinical evaluation in labor is not very accurate, therefore ultrasound is one of the instruments that can give us a more objective assessment than the clinical evaluation. Objectives: In this study, we investigate the magnitude of the angle of progression (AoP) at the second stage of labor in fetuses with cephalic presentation and its relation to spontaneous vaginal delivery. Patients and Methods: In this cross-sectional study, we measured the AoP using trans-perineal sonography in the 2nd stage of the labor and compared AoP in normal vaginal delivery (NVD), cesarean and NVD with vacuum groups on 80 pregnant women. We also investigated the correlation between AoP and induction time and duration of the second stage of labor. Results: In 80 study patients, 54 (67.5 %) had normal vaginal deliveries, 21 (26.2 %) had cesarean section and 5 (6.2%) had NVD with a vacuum. There was a statistically significant difference between NVD, cesarean section, and NVD with vacuum in terms of the AoP (P<0.01). There was a statistically significant correlation between AoP and induction time, duration of 2nd stage of labor and Apgar scores (P<0.05). Conclusion: Higher progression angle is associated with shorter induction time and 2nd stage of labor, higher neonatal Apgar scores and a higher chance of spontaneous vaginal delivery which makes it an appropriate index for predicting pregnancy outcomes.

The Assessment of Intrapartum Transperineal Ultrasonographic Parameters for their Effectiveness in Evaluation of Progress of Labor and Prediction of Mode of Delivery in Egyptian Women

Introduction: High fetal head station has been associated with prolonged labor and delivery outcomes. Although clinical assessment of fetal head station is both subjective and unreliable, women with prolonged labor are subjected to multiple digital vaginal examinations. The use of ultrasound has been proposed to aid in the management of labor since 1990s. Ultrasound examination is more accurate and reproducible than clinical examination in the diagnosis of fetal head station and in the prediction of arrest of labor. Ultrasound examination can, to some extent, distinguish those women destined for spontaneous vaginal delivery and those destined for operative delivery and may predict the outcome of instrumental vaginal delivery. Such a technique has the potential to reduce the frequency of intrusive internal examinations and associated infection and could be useful in allowing the assessment of women in whom digital VE is traumatic or contra-indicated. Intrapartum ultrasound not only provides objective and quantitative data in labor, but also helps to make more reliable clinical decisions aiming to improve obstetric outcomes of both the mother and fetus as a supplementary tool for active management. Aim of the work: This study aims at assessing the value of intrapartum transperineal ultrasonography as a quantitative and objective tool in the evaluation of progress of labor and prediction of mode of delivery. Subjects: This study was a prospective observational study conducted on 600 primiparous women in active first stage of labor admitted to Kasr Al Ainy maternity hospital from January 2017 to June 2018. The studied population was divided into two groups. Group A of 300 women with normal progress of labor and group B of 300 women with prolonged 1st stage of labor. Methods: Fetal head station(FHS) was assessed clinically by digital vaginal examination (dVE) and sonographically by transperineal ultrasound measurement of head perineal distance (HPD) and angle of progression (AOP). Intrapartum care of the patient continued as normal based only on digital vaginal examinations using the modified WHO partogram. (1). Statistical analysis was targeted towards assessing the potential of the intrapartum ultrasonography in the evaluation of progress of labor and prediction of mode of delivery. Results: All studied parameters for assessment of FHS (dVE, HPD, and AOP) significantly corelated with each other and with both progress of labor and mode of delivery with P value (<0.001). The highest sensitivity for prediction of progress of labor is observed using dVE (83%), the highest specificity is observed using AOP (78.3%). The highest sensitivity for prediction mode of delivery is for combined HPD & AOP (97.7%) while the highest specificity is for AOP (81%). When combining both HPD and AOP for prediction of mode of delivery, the assessment of both parameters was found to have a high sensitivity of 97.7% and a high positive predictive value of 86.63%. Conclusion: Intrapartum ultrasound examination is a valuable tool in the prediction of progress of labor and mode of delivery. The assessment of fetal head station by transperineal ultrasound measurement of HPD and AOP is much more informative of the progress of labor and the mode of delivery than digital assessment of fetal head station. Keywords: Labor, intrapartum ultrasound, Angle of progression, Head perineal distance, fetal head station, digital vaginal examination.

Sonographic Risk Assessment for An Unplanned Operative Delivery: A Prospective Study

Purpose: To assess the value of pre-labor maternal and fetal sonographic variables to predict an unplanned operative delivery.Methods: In this prospective study, nulliparous women were recruited at 37.0-42.0 weeks of gestation. Sonographic measurements included estimated fetal weight, maternal pubic arch angle, and the angle of progression. We performed a descriptive and comparative analysis between two outcome groups: spontaneous vaginal delivery (SVD) and unplanned operative delivery (UOD) (vacuum-assisted, forceps-assisted and cesarean deliveries). Multivariate logistic regression with ROC analysis was used to create discriminatory models for UOD. Results: Among 234 patients in the study group, 175 had a spontaneous vaginal delivery and 59 an unplanned operative delivery. Maternal height and pubic arch angle (PAA) significantly correlated with UOD. Analysis of Maximum Likelihood Estimates revealed a multivariate model for the prediction of UOD, including the parameters of maternal age, maternal height, sonographic PAA, angle of progression (AOP), and estimated fetal weight, with an area under the curve of 0.7118. Conclusion: Sonographic parameters representing maternal pelvic configuration (PAA) and maternal-fetal interface (AOP) improve the prediction ability of pre-labor models for a UOD. These data may aid the obstetrician in the counseling process before delivery.

Evaluation of the labour process with serial transperineal ultrasonography and prediction of the type of birth

ObjectivesThe purpose of this study is to follow the birth process with transperineal ultrasonography (TPU) and predict the delivery method using angle of progression (AOP).MethodsThe study included 134 patients. The AOP was examined with TPU in the lithotomy position applied at 4-h intervals, not at a time of straining or contractions. The relationship was examined between AOP and those who continued with vaginal delivery, and those who underwent caesarean section delivery.ResultsA total of 122 (91%) patients had vaginal delivery and 12 (9%) patients had cesarean delivery. In patients giving vaginal delivery, progress in AOP was observed in every 4-h measurement, but not in patients with cesarean section. In the ROC analysis, if 70% sensitivity and 75% specificity with AOP degree >132.5°, the patient was expected to have vaginal delivery with a probability of 77.5% (95% CI 0.62–0.93; p=0.002).ConclusionsRather than repeating digital examinations, the labour process can be monitored with serial TPU and the type of delivery can be predicted. There is a need for further studies for the measurement of AOP with TPU to become a part of clinical practice in the monitoring of the whole labour process.

The Role of Intrapartum Ultrasound to Predict Outcome of Delivery

Objective: To predict outcome of delivery by using ultrasound measurements consisting angle of progression, and head perineum distance.Methods: Sixtytwo parturients assigned in cohort prospective study. Ultrasound examination begin with identifying the cephalic position by placement of transducer on suprapubic region. The angle of progression is obtained trans-labially, head perineum distance and cervical dilation trans-perineally. Ultrasound findings of Nuchal cord, caput, moulding, occiput posterior position then compared with conventional findings. Labour is observed, outcomes are grouped into vaginal delivery and cesarean section.Results: Thirty-six women went for vaginal delivery, 26 underwent cesarean section. Independent T-test showed significant differences of the angle of progression (121.11o vs 88.85o) and head perineum distance (5.15 cm vs 7.26 cm) between the two groups. Linear regression test found a negative correlation on how the angle of progression affecting head perineum distance p-value <0.05 , R2 0.684, (r) – 0.827. Cervical dilation measurements both ultrasound and digital examination were assessed with the Bland-Altman reliability test with level of agreement (-1.0 cm) – (1.2 cm). Receiver Operating Characteristic curve showed cut-off value >101o angle of progression predicts vaginal delivery, area under curve 0.902 and positive likelihood ratio 4.4. Kappa reliability testing for nuchal cord, caput, moulding, and occiput posterior are 0.919, 0.938, 0.384, 0.681 respectively.Conclusion: Intrapartum ultrasound able to predict the outcome of delivery, digital examination of cervical dilation is the mainstay of measurement. Ultrasound able to rule out the presence of nuchal cord, caput, and occiput posterior. Keywords: angle of progression, head perineum distance, intrapartum ultrasound. Abstrak Tujuan: Mengetahui besar sudut penurunan kepala dan jarak kepala ke perineum dengan ultrasonografi intrapartum dalam memprediksi luaran persalinan. Metode: Enam puluh dua ibu bersalin dilakukan pemeriksaan ultrasonografi intrapartum. Identifikasi posisi kepala dengan meletakan transduser di suprapubik, sudut penurunan kepala secara translabial, jarak kepala ke perineum dan nilai dilatasi serviks secara transperineal. Lilitan tali pusat, kaput, molase, dan oksiput posterior pada temuan ulstrasonografi dibandingkan dengan hasil pemeriksaan konvensional. Observasi persalinan dilakukan, di kelompokan untuk persalinan pervaginam dan seksio sesarea.Hasil: Didapatkan 36 persalinan pervaginam dan 26 seksio sesarea. Uji – t secara signifikan berbeda, nilai sudut penurunan kepala (121,11o vs 88,85o), jarak kepala ke perineum (5,15 cm vs 7,26 cm) pada kedua kelompok. Uji regresi linier sudut penurunan kepala dan pengaruhnya terhadap jarak kepala ke perineum berkorelasi negatif p <0.05, R2 0.684, (r) – 0.827. Batas kesepakatan nilai dilatasi serviks kedua metode diuji dengan uji reliabilitas Bland-Altman dengan batas kesepakatan sebesar (-1.0) cm – (1.2) cm. Sudut penurunan kepala memprediksi persalinan pervaginam sebesar >101o, uji diagnostik dengan kurva Receiver Operating Characteristic didapatkan area dibawah kurva 0.902, rasio kemungkinan positif 4,4. Uji reliabilitas Kappa lilitan tali pusat, kaput ,molase, dan oksiput posterior berturut-turut (k) = 0.919, 0.938, 0.384, dan 0.681. Kesimpulan: Penggunaan ultrasonografi intrapartum dapat memprediksi luaran persalinan, pemriksaan dalam tetap menjadi pemeriksaan utama dalam menilai dilatasi serviks, ultrasnografi mampu mendeteksi lilitan tali pusat, kaput, dan posisi oksiput posterior.Kata kunci: Jarak kepala ke perineum, sudut penurunan kepala, Ultrasonografi intrapartum.