Ferumoxytol-enhanced MR demonstration of changes to internal placental structure in placenta accreta spectrum: Preliminary findings.

INTRODUCTION: The goal of this pilot study is to determine if ferumoxytol-enhanced MR might provide a new approach to the diagnosis of placenta accreta spectrum (PAS), and if so, to identify signs of PAS. METHODS: Ten pregnant women were referred for MRI evaluation for PAS. MR studies consisted of pre-contrast SSFSE, SSFP, DWI, and ferumoxytol-enhanced sequences. Post-contrast images were rendered as MIP and MinIP images to separately display the maternal and fetal circulations respectively. Two readers examined the images for architectural changes to placentone (fetal cotyledon) that might distinguish PAS cases from normal. Attention was given to the size and morphology of the placentone, villous tree, and vascularity. In addition, the images were examined for evidence of fibrin/fibrinoid, intervillous thrombus, basal and chorionic plate bulges. Interobserver agreement was characterized with kappa coefficients and levels of confidence for feature identification was recorded on a 10-point scale. RESULTS: At delivery, there were five normal placentas and five with PAS (one accreta, two increta, two percreta). The ten changes of placental architecture in PAS included: focal/regional expansion of placentone(s); lateral displacement and compression of the villous tree; disruption of a regular pattern of normal placentones; bulging of the basal plate; bulging of the chorionic plate; transplacental stem villi; linear/nodular bands at basal plate; non-tapering villous branches; intervillous hemorrhage; and dilated subplacental vessels. All these changes were more common in PAS; the first five achieved statistical significance in this small sample. The interobserver agreement and confidence for the identification of these features was good to excellent except for dilated subplacental vessels. DISCUSSION: Ferumoxytol-enhanced MR imaging appears to depict derangements of the internal architecture of placentas with PAS, thereby suggesting a promising new strategy to diagnose PAS.

Placenta accreta spectrum: the pattern and character of intraplacental blood flow by color and spectral Doppler.

PURPOSE: To characterize intraplacental blood flow patterns in placenta accreta spectrum (PAS) with color and spectral Doppler imaging. METHODS: Thirty-two patients at risk for PAS underwent ultrasound imaging with both color and spectral Doppler. The placenta was inspected for areas of vascularity by color Doppler, particularly within the lower uterine segment. Spectral Doppler waveforms were obtained from these vessels and categorized as either intraplacental or subplacental (myometrial), venous or arterial, fetal or maternal (based on heart rate). Arterial waveforms were measured for heart rate, peak systolic velocity, end diastolic velocity, and resistive index. Statistical comparisons were made between cases with and without PAS using Fisher exact tests (categorical variables) and Mann-Whitney U tests (numerical indices). Interobserver agreement was characterized with kappa coefficients. RESULTS: At delivery, there were 19 cases with PAS and 13 without PAS. On ultrasound studies, clustered intraplacental vascularity was found in the lower uterine segment in 66% of cases (95% of PAS cases and 23% cases without PAS; p < 0.0001). Maternal arterial waveforms were found within the vascular cluster in 84% of PAS cases and 15% of cases without PAS (p < 0.0001). A traversing fetal artery was found within the vascular cluster in 56% of cases (84% PAS cases and 15% cases without PAS; p = 0.001). Venous waveforms were found in 84% of PAS cases and 15% of cases without PAS. Interobserver agreement was good to excellent. CONCLUSION: Intraplacental blood flow pattern in PAS is characterized by an intraplacental vascular cluster containing low-resistance maternal arterial flow and transplacental fetal arteries.

Prediction Model for Vaginal Birth After Induction of Labor in Women With Hypertensive Disorders of Pregnancy.

OBJECTIVE: To identify characteristics associated with vaginal delivery compared with cesarean delivery after labor induction among women with hypertensive disorders of pregnancy and to develop and validate a prediction model to assist in clinical care. METHODS: We studied a retrospective cohort of women with singleton pregnancies who had hypertensive disorders of pregnancy and who underwent induction of labor at 34 weeks of gestation or more from January 1, 2002, to March 31, 2013. Exclusion criteria included spontaneous labor, prelabor cesarean delivery, and known fetal anomalies. The study cohort was randomly divided into two groups; 70% of pregnancies were used to identify characteristics associated with vaginal delivery and develop a prediction model, and 30% were used to internally validate the model. Candidate predictors were limited to those associated with cesarean delivery and were available to a practitioner at time of induction. Stepwise backward logistic regression was used to build the most parsimonious model predicting cesarean delivery. Hosmer-Lemeshow test was used to assess goodness-of-fit. Model discrimination was evaluated using the concordance index and displayed through the area under the receiver operating characteristic curve (AUC). RESULTS: Of the 1,357 women meeting study criteria, 974 (71.8%) had a vaginal delivery. The final model consisted of eight variables: maternal age, body mass index, gestational age, intrapartum magnesium sulfate for seizure prophylaxis, need for cervical ripening, prior cesarean delivery and cervical dilation, and effacement. Model calibration and discrimination were satisfactory with Hosmer-Lemeshow test P=.35 and with a 95% CI, an AUC of 0.76 (0.73-0.79). Among those with predicted probability of cesarean delivery of 20% or less, 89.5% had a vaginal delivery. Internal validation demonstrated similar discriminatory ability. CONCLUSION: Using information available before labor induction, and contingent on future external validation, our model can help women better understand their likelihood of vaginal delivery success when undergoing induction of labor for hypertensive disorders of pregnancy.

Intrapartum Glucose Management in Women With Gestational Diabetes Mellitus: A Randomized Controlled Trial.

OBJECTIVE: To assess the effect of tight compared with liberalized intrapartum maternal glucose management on neonatal hypoglycemia risk in pregnancies complicated by gestational diabetes mellitus (GDM). METHODS: This was a randomized controlled trial of women with singleton gestations and GDM attempting vaginal delivery. After written informed consent, women were randomly allocated to one of two intrapartum maternal glucose management protocols: tight control (glucose measurements hourly and treatment for maternal glucose levels lower than 60 mg/dL or greater than 100 mg/dL) or liberalized control (glucose measurements every 4 hours and treatment for maternal glucose levels lower than 60 mg/dL or greater than 120 mg/dL). The primary outcome was the first neonatal blood glucose level; a total sample size of 74 was necessary to have 80% power to detect a mean difference of 10 mg/dL between groups. Secondary outcomes included neonatal blood glucose concentrations within the first 24 hours of life, number of glucose treatments (intravenous or oral) received to treat neonatal hypoglycemia, neonatal intensive care unit admission, and neonatal hyperbilirubinemia. RESULTS: From February 2016 to April 2018, 76 women were randomized (38 in each group), and all were included in the analysis. Baseline characteristics of the two groups were comparable for all relevant obstetric variables; mean gestational age was 39 weeks in both groups. Antepartum, two thirds of women in each group were treated medically (almost exclusively with insulin). The primary outcome was similar between the tight and liberalized control groups: 53 mg/dL vs 58 mg/dL, mean difference -4.18, 95% CI -12.66 to 4.29. However, mean neonatal glucose level within the first 24 hours of life was lower in the tight control group: 54 mg/dL vs 58 mg/dL, mean difference -3.39, 95% CI -7.07 to 0.29. Other secondary outcomes were similar between groups. CONCLUSION: A protocol aimed at tight maternal glucose management in labor compared with liberalized management for women with GDM did not result in better initial neonatal glucose concentrations and was associated with lower mean neonatal blood glucose levels in the first 24 hours of life. This study supports raising the upper threshold for intrapartum maternal glucose and decreasing the frequency of intrapartum glucose assessment for women with GDM. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02596932.