Comparison of different methods of measuring angle of progression in prediction of labor outcome.

OBJECTIVES: First, to compare the manual sagittal and parasagittal and automated parasagittal methods of measuring the angle of progression (AoP) by transperineal ultrasound during labor, and, second, to develop models for the prediction of time to delivery and need for Cesarean section (CS) for failure to progress (FTP) in a population of patients undergoing induction of labor. METHODS: This was a prospective observational study of transperineal ultrasound in a cohort of 512 women with a singleton pregnancy undergoing induction of labor. A random selection of 50 stored images was assessed for inter- and intraobserver reliability of AoP measurements using the manual sagittal and parasagittal and automated parasagittal methods. In cases of vaginal delivery, univariate linear, multiple linear and quantile regression analyses were performed to predict time to delivery. Univariate and multivariate binomial logistic regression analyses were performed to predict CS for FTP in the first stage of labor. RESULTS: The intraclass correlation coefficient (ICC) for the manual parasagittal method for a single observer was 0.97 (95% CI, 0.95-0.98) and for two observers it was 0.96 (95% CI, 0.93-0.98), indicating good reliability. The ICC for the sagittal method for a single observer was 0.93 (95% CI, 0.88-0.96) and for two observers it was 0.74 (95% CI, 0.58-0.84), indicating moderate reliability for a single observer and poor reliability between two observers. Bland-Altman analysis demonstrated narrower limits of agreement for the manual parasagittal approach than for the sagittal approach for both a single and two observers. The automated parasagittal method failed to capture an image in 19% of cases. The mean difference in AoP measurements between the sagittal and manual parasagittal methods was 11°. In pregnancies resulting in vaginal delivery, 54% of the variation in time to delivery was explained in a model combining parity, epidural and syntocinon use during labor and the sonographic findings of fetal head position and AoP. In the prediction of CS for FTP in the first stage of labor, a model which combined maternal factors with the sonographic measurements of AoP and estimated fetal weight was superior to one utilizing maternal factors alone (area under the receiver-operating-characteristics curve, 0.80 vs 0.76). CONCLUSIONS: First, the method of measuring AoP with the greatest reliability is the manual parasagittal technique and future research should focus on this technique. Second, over half of the variation in time to vaginal delivery can be explained by a model that combines maternal factors, pregnancy characteristics and ultrasound findings. Third, the ability of AoP to provide clinically useful prediction of CS for FTP in the first stage of labor is limited. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Procedure-related risk of miscarriage following chorionic villus sampling and amniocentesis.

OBJECTIVES: To estimate the procedure-related risks of miscarriage following chorionic villus sampling (CVS) and amniocentesis in a large unselected screened population, and to determine whether these risks are consistent with those reported in systematic reviews and meta-analyses. METHODS: This was a retrospective cohort study carried out on data obtained from a large fetal medicine unit in the UK between January 2009 and May 2018. We included all women with singleton pregnancy who booked for pregnancy care at our unit before 20 weeks' gestation, after excluding those with multiple pregnancy, major fetal defect, pregnancy termination and loss to follow-up. We estimated the risk of miscarriage in women who underwent a CVS or amniocentesis as well as in those who did not have an invasive procedure. The procedure-related risk of miscarriage was estimated as risk difference (95% CI) between the two groups. Univariate and multivariate regression analyses were used to derive odds ratios (95% CI) and determine which maternal and pregnancy characteristics provided a significant contribution in the prediction of miscarriage and whether CVS or amniocentesis provided a significant independent contribution. RESULTS: During the study period, 45 120 singleton pregnancies were booked for pregnancy care at our hospital, of which 1546 had an invasive procedure. We excluded 1429 (3.2%) pregnancies due to fetal defects, termination of pregnancy or missing outcomes. Of the 43 691 pregnancies included in the study population, 861 underwent CVS and 375 amniocentesis. In pregnancies that underwent CVS, the risk of miscarriage was 1.5% (13/861), compared with 1.2% (476/39 152) in pregnancies that had first-trimester combined screening and did not have an invasive procedure (P = 0.437). In pregnancies that underwent an amniocentesis, the risk of miscarriage was 0.8% (3/375), compared with 1.2% (491/42 463) in those that did not undergo an invasive procedure (P = 0.520). Univariate and multivariate regression analysis demonstrated that there was no significant contribution in the prediction of the risk of miscarriage from CVS (P = 0.399 and P = 0.592, respectively) or amniocentesis (P = 0.543 and P = 0.550, respectively). The risk of procedure-related loss attributed to CVS was 0.29% (95% CI, -0.53 to 1.12%) and that following amniocentesis was -0.36% (95% CI, -1.26 to 0.55%), which was not significantly different from the risk in women who did not have any procedure. CONCLUSIONS: The procedure-related risks of miscarriage following CVS and amniocentesis in our study are considerably lower than those currently quoted and are consistent with the estimates of such risks reported by systematic reviews and meta-analyses. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Prediction of adverse perinatal outcome by cerebroplacental ratio in women undergoing induction of labor.

OBJECTIVE: To investigate the performance of screening for adverse perinatal outcome by the cerebroplacental ratio (CPR) measured within 24 h prior to induction of labor. METHODS: This was a prospective observational study of 1902 singleton pregnancies undergoing induction of labor at ≥ 37 weeks' gestation. Doppler ultrasound was used to measure the pulsatility index (PI) in the umbilical artery (UA) and fetal middle cerebral artery (MCA) within 24 h before induction of labor. The measured UA-PI and MCA-PI and their ratio were converted to multiples of the median after adjustment for gestational age. Univariable and multivariable logistic regression analysis was used to determine whether CPR improved the prediction of adverse perinatal outcome provided by maternal characteristics, medical history and obstetric factors. The detection rate (DR) and false-positive rate (FPR) of screening by CPR were estimated for Cesarean section for presumed fetal distress and adverse neonatal outcome, which included umbilical arterial or venous cord blood pH ≤ 7 and ≤ 7.1, respectively, 5-min Apgar score < 7, admission to the neonatal intensive care unit for > 24 h or hypoxic ischemic encephalopathy. RESULTS: A combination of maternal and pregnancy characteristics, including age, weight, racial origin, previous obstetric history, pre-eclampsia, gestational age at delivery and amniotic fluid volume, identified 39% of pregnancies requiring Cesarean section for fetal distress at a FPR of 10%; addition of CPR did not improve the performance of screening. In screening for adverse neonatal outcome by a combination of parity and CPR, the DR was 17% at a FPR of 10%. CONCLUSION: Low CPR, measured within 24 h prior to induction of labor, is associated with increased risk of Cesarean section for fetal distress and adverse neonatal outcome, but the performance of CPR for such surrogate measures of fetal hypoxic morbidity is poor. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.