Magnetic Resonance Imaging-Based Nomogram to Antenatal Predict Cesarean Delivery for Cephalopelvic Disproportion in Primiparous Women.

BACKGROUND: Cephalopelvic disproportion (CPD)-related obstructed labor is associated with maternal and neonatal morbidity and mortality. Accurate prediction of whether a primiparous woman is at high risk of an unplanned cesarean delivery would be a major advance in obstetrics. PURPOSE: To develop and validate a predictive model assessing the risk of cesarean delivery in primiparous women based on MRI findings. STUDY TYPE: Prospective. POPULATION: A total of 150 primiparous women with clinical findings suggestive of CPD. FIELD STRENGTH/SEQUENCE: T1-weighted fast spin-echo sequences, single-shot fast spin-echo (SSFSE) T2-weighted sequences at 1.5 T. ASSESSMENT: Pelvimetry and fetal biometry were assessed independently by two radiologists. A nomogram model combined that the clinical and MRI characteristics was constructed. STATISTICAL TESTS: Univariable and multivariable logistic regression analyses were applied to select independent variables. Receiver operating characteristic (ROC) analysis was performed, and the discrimination of the model was assessed by the area under the curve (AUC). Calibration was assessed by calibration plots. Decision curve analysis was applied to evaluate the net clinical benefit. A P value below 0.05 was considered to be statistically significant. RESULTS: In multivariable modeling, the maternal body mass index (BMI) before delivery, bilateral femoral head distance, obstetric conjugate, fetal head circumference, and fetal abdominal circumference was significantly associated with the likelihood of cesarean delivery. The discrimination calculated as the AUC was 0.838 (95% confidence interval [CI]: 0.774-0.902). The sensitivity and specificity of the nomogram model were 0.787 and 0.764, and the positive predictive and negative predictive values were 0.696 and 0.840, respectively. The model demonstrated satisfactory calibration (calibration slope = 0.945). Moreover, the decision curve analysis proved the superior net benefit of the model compared with each factor included. DATA CONCLUSION: Our study might provide a nomogram model that could identify primiparous women at risk of cesarean delivery caused by CPD based on MRI measurements. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

The Relation between Head Circumference and Mid-Pelvic Circumference: A Simple Index for Cephalopelvic Disproportion Evaluation.

INTRODUCTION: Cephalopelvic disproportion (CPD) is one of the most common obstetric complications. Since CPD is the disproportion between the fetal head and maternal bony pelvis, evaluation of the head circumference (HC) relative to the maternal bony pelvis may be a useful adjunct to pre-labor CPD evaluation. The aim of the present study was a proof-of-concept evaluation of the ratio between HC and pelvic circumference (PC) as a predictor of CPD. METHODS: Of 11,822 deliveries, 104 cases that underwent an abdominopelvic CT for any medical indication and who underwent normal vaginal deliveries (NVDs) (n = 84) or cesarean deliveries (CD) due to CPD (n = 20) were included retrospectively. Maternal pelvis dimensions were reconstructed and neonatal HC, as a proxy for fetal HC, was measured. The correlation between cases of CPD and cephalopelvic circumference index (CPCI), which represents the ratio between the HC and PC in percentage (HC/PC × 100), was evaluated. RESULTS: The mid-pelvis CPCI (MP-CPCI) was larger in CD groups as compared to the NVD group: 103 ± 11 versus 97 ± 8%, respectively (p = 0.0003). In logistic regression analysis, the MP-CPCI was found to be independently associated with CD due to CPD: each 1% increase in MP-CPCI increased the likelihood of CD for CPD by 11% (adjusted odds ratio [aOR] 1.11, 95% CI, 1.03-1.19, p = 0.004). The aOR for CD due to CPD increased incrementally as the MP-CPCI increased, from 3.56 (95% CI, 1.01-12.6) at MP-CPCI of 100 to 5.6 (95% CI, 1.63-19.45) at 105, 21.44 (95% CI, 3.05-150.84) at 110, and 28.88 (95% CI, 2.3-362.27) at MP-CPCI of 115. CONCLUSIONS: The MP-CPCI, representing the relative dimensions of the fetal HC and maternal PC, is a simple tool that can potentially distinguish between parturients at lower and higher risk of CPD. Prospective randomized studies are required to evaluate the feasibility of prenatal pelvimetry and MP-CPCI to predict the risk of CPD during labor.

Antepartum evaluation of the obstetric conjugate at transabdominal 2D ultrasound: A feasibility study.

INTRODUCTION: The obstetric conjugate represents the shortest anteroposterior diameter of the birth canal and it reflects the capacity of the pelvic inlet to allow the passage and the engagement of the fetal head. The antepartum evaluation of this parameter may be attempted at digital examination to predict the risk of cephalopelvic disproportion, but the accuracy of clinical pelvimetry is notoriously poor. The aim of our study was to describe the sonographic measurement of the obstetric conjugate at transabdominal 2D-ultrasound and to assess its reproducibility. MATERIAL AND METHODS: This is a prospective cohort study conducted at a tertiary University hospital. A non-consecutive series of pregnant women with uncomplicated singleton pregnancies attending the antenatal clinic for routine booking from 34 weeks of gestation onward were included. The ultrasound probe was longitudinally placed above the level of the symphysis and the interpubic fibrocartilaginous disk was visualized. Then the promontory was identified as the most prominent segment of the sacral vertebral column. The obstetric conjugate was measured as the distance between the inner edge of the interpubic disk and the promontory. The inter- and intraobserver repeatability of this measurement was calculated using the intraclass correlation coefficient (ICC) and the Bland-Altman method. RESULTS: In all, 119 women were considered eligible for the study; of these, 111/119 (93.3%) women were included in the analysis with a median gestational age of 36.0 (35.0-37.0) weeks. The mean obstetric conjugate measurement was 11.4 ± 0.93 mm for the first operator and 11.4 ± 0.91 mm for the second operator. The overall interobserver ICC was 0.95 (95% [confidence interval] CI 0.92-0.96) and the overall intraobserver ICC was 0.97 (95% CI 0.96-0.98). Limits of agreement ranged from -0.84 to 0.80 for interobserver measures and from -0.64 to 0.62 for intraobserver measures. The degree of reliability was also analyzed for women with a body mass index ≥30 and for women with a gestational age ≥37 weeks. The inter- and intraobserver ICCs were respectively 0.97 (95% CI 0.90-0.98) and 0.98 (0.95-0.99) in the former group and 0.96 (95% CI 0.93-0.98) and 0.97 (95% CI 0.95-0.98) in the latter group. CONCLUSIONS: Our study demonstrated that among pregnant women at term gestation, sonographic measurement of the obstetric conjugate is feasible and reproducible.

Assessment of Acute Obstetrical Needs and the Potential Utility of Point-Of-Care Ultrasound in the North East Region of Haiti: A Cross-Sectional Study.

Background: Point-of-care ultrasound (POCUS) implemented through task shifting to nontraditional users has potential as a diagnostic adjuvant to enhance acute obstetrical care in resource-constrained environments with limited access to physician providers. Objective: This study evaluated acute obstetrical needs and the potential role for POCUS programming in the North East region of Haiti. Methods: Data was collected on all women presenting to the obstetrical departments of two Ministry of Public Health and Population (MSPP)-affiliated public hospitals in the North East region of Haiti: Fort Liberté Hospital and Centre Medicosocial de Ouanaminthe. Data was obtained via retrospective review of hospital records from January 1 through March 31, 2016. Trained personnel gathered data on demographics, obstetrical history, diagnoses, clinical care and outcomes using a standardized tool. Diagnoses a priori, defined as those diagnoses whose detection could be assisted with POCUS, included multi-gestations, non-vertex presentation, cephalopelvic disproportion, placental abruption, placenta previa, spontaneous abortions, retained products and ectopic pregnancy. Results: Data were collected from 589 patients during the study period. Median maternal age was 26 years and median gestational age was 38 weeks. The most common reason for seeking care was pelvic pain (85.2%). Sixty-seven (11.5%) women were transferred to other facilities for higher-level care. Among cases not transferred, post-partum hemorrhage, infant mortality and maternal mortality occurred in 2.4%, 3.0% and 0.6% of cases, respectively. There were 69 cases with diagnoses that could have benefited from POCUS use. Between sites, significantly more cases had the potential for improved diagnostics with POCUS at Fort Liberté Hospital (19.8%) than Centre Medicosocial de Ouanaminthe (8.2%) (p < 0.001). Conclusion: Acute obstetrical care is common and POCUS has the potential to impact the care of obstetrical patients in the North East region of Haiti. Future programs evaluating the feasibility of task shifting and the sustainable impacts of acute obstetric POCUS in Haiti will be important.

[Development of CT Pelvimetry Using Deep Learning Based Reconstruction].

PURPOSE: X-ray pelvimetry is typically performed for the diagnosis of the cephalopelvic disproportion (CPD). The purpose of this study was to assess the utility of new computed tomography (CT) reconstruction "deep learning based reconstruction (DLR) " in ultra-low dose CT pelvimetry. METHOD: CT pelvimetry was performed 320-row CT. All CT images were reconstructed with and without DLR and transferred for workstation to processing martius and guthmann view. Radiologist and obstetrician-gynecologist subjectively ranked overall image quality of each CT image from the best to the worst. Exposure dose of the CT pelvimetry used a following calculated value, displayed CT dose index (CTDI) vol multiplied by measured value using the thimble chamber and pelvic phantom, and of the X-ray pelvimetry used Japan-Diagnositic Refernce Levels 2015 as a reference, were compared. RESULT: 3D images obtained from CT pelvimetry with DLR showed accurate biparietal diameter and obstetric conjugate as compared to without DLR. Radiation dose of CT pelvimetry is 0.39 mGy, of X-ray pelvimetry is 1.18 mGy, respectively. Conculusion: Although the visualizing high contrast object, such as bone morphology, is likely to reduce exposure dose in CT examination generally, DLR enable to further dose reduction to keep image quality. 3D image processing from CT pelvimetry solves the problem of expansion rate in X-P pelvimetry and provide accurate measurements. Furthermore, CT pelvimetry can undergo more comfortable position for Pregnant Woman in Labor.

A safe, low-cost, easy-to-use 3D camera platform to assess risk of obstructed labor due to cephalopelvic disproportion.

Cephalopelvic disproportion (CPD)-related obstructed labor is accountable for 3-8% of the maternal deaths worldwide. The consequence of CPD-related obstructive labor in the absence of a Caesarian section (C/S) is often maternal or perinatal mortality or morbidity to the mother and/or the infant. Accurate and timely referral of at-risk mothers to health facilities where C/S is a delivery option could reduce maternal mortality in the developing world. The goal of this work was to develop and test the feasibility of a safe, low-cost, easy-to-use, portable tool, using a Microsoft Kinect 3D camera, to identify women at risk for obstructed labor due to CPD. Magnetic resonance imaging (MRI) scans, 3D camera imaging, anthropometry and clinical pelvimetry were collected and analyzed from women 18-40 years of age, at gestational age ≥36+0 weeks with previous C/S due to CPD (n = 43), previous uncomplicated vaginal deliveries (n = 96), and no previous obstetric history (n = 148) from Addis Ababa, Ethiopia. Novel and published CPD risk scores based on anthropometry, clinical pelvimetry, MRI, and Kinect measurements were compared. Significant differences were observed in most anthropometry, clinical pelvimetry, MRI and Kinect measurements between women delivering via CPD-related C/S versus those delivering vaginally. The area under the receiver-operator curve from novel CPD risk scores base on MRI-, Kinect-, and anthropometric-features outperformed novel CPD risk scores based on clinical pelvimetry and previously published indices for CPD risk calculated from these data; e.g., pelvic inlet area, height, and fetal-pelvic index. This work demonstrates the feasibility of a 3D camera-based platform for assessing CPD risk as a novel, safe, scalable approach to better predict risk of CPD in Ethiopia and warrants the need for further blinded, prospective studies to refine and validate the proposed CPD risk scores, which are required before this method can be applied clinically.

Study on the cephalopelvic relationship with cephalic presentation in nulliparous full-term Chinese pregnant women by MRI with three-dimensional reconstruction.

PURPOSE: To analyze the relationship between fetal head size and maternal pelvis size using magnetic resonance imaging (MRI) with a 3-D reconstruction technique. METHODS: A total of 301 nulliparous full-term Chinese pregnant women with cephalic presentation were enrolled and received MRI examinations before labor onset. Data were collected and imported into Mimics software to reconstruct the maternal pelvis and fetus. RESULTS: Of 301 pregnant women, 212 underwent vaginal delivery and 32 received cesarean section. The body mass index (BMI) was significantly different between the vaginal delivery group and the suspected cephalopelvic disproportion (CPD) group; the larger the BMI, the higher was the risk of CPD. The transverse diameter of the pelvic inlet and the posterior sagittal diameter of the midpelvis were significantly larger in the vaginal delivery group, compared with the suspected CPD group. Fetal weight > 3.5 kg could be used as a diagnostic indicator for CPD. CONCLUSIONS: BMI is a risk factor for CPD, and fetal weight < 3.5 kg is an important diagnostic indicator for natural delivery in Chinese pregnant women.

MR pelvimetry: prognosis for successful vaginal delivery in patients with suspected fetopelvic disproportion or breech presentation at term.

PURPOSE: The purpose of this study was to correlate MR pelvimetric pelvic inlet measurements with mode of delivery and neonatal outcome in patients with suspected fetopelvic disproportion or breech presentation. METHODS: For this retrospective monocentric study, 237 consecutive MR pelvimetry reports (1999-2016) of pregnant women due to either suspected fetopelvic disproportion, pelvic deformation after trauma, or persistent breech presentation were retrieved from the radiologic database and matched with corresponding information from the obstetric database. RESULTS: Of 223 included women, 95 (42.6%) underwent planned cesarean section (pCS) and 128 (57.4%) underwent a trial of vaginal labour (TOL), of whom 93 (72.7%) delivered vaginally. Vaginal delivery was successful in 45 out of 64 (70.3%) cephalic cases and in 48 out of 64 (75.0%) breech cases. We found statistically significant differences in conjugata vera obstetrica (CV) and diameter transversalis (DT) between the groups TOL and pCS (CV: 12.5 ± 1.0 vs 12.1 ± 1.2 cm, p value 0.001; DT: 13.3 ± 0.9 vs 12.7 ± 0.9 cm, p value <0.001, respectively). However, there was no significant difference between successful VD and cesarean section after TOL (CV: 12.5 ± 0.9 vs 12.3 ± 1.1 cm, p value 0.194; DT: 13.4 ± 0.9 vs 13.2 ± 0.9 cm, p value 0.358, respectively). CONCLUSIONS: In our cohort, MR pelvimetry was a useful tool for prepartal assessment of the female pelvis in the selection of TOL candidates. Yet, it does not seem to yield additional predictive value for women with a previous vaginal delivery.

Can Ultrasound Performed in Prolonged Second Stage of Labor Predict the Difficulty and Success Rates of Operative Vaginal Delivery?

OBJECTIVE: To evaluate different sonographic methods for the prediction of the difficulty and the success of operative vaginal delivery (OPD). MATERIALS AND METHODS: A prospective study was performed on 45 term singleton uncomplicated pregnancies with prolonged 2nd stage of delivery with cephalic presentation. Measurements of the fetal head, relations between the fetal head and maternal pelvic parameters during rest and during maternal pushing were taken using translabial ultrasound. RESULTS: 29 cases of OPD were successful and 4 cases failed ending in cesarean section. The passage of the biparietal diameter (BPD) of the infrapubic line (IPL) was statistically correlated with the success of OPD. Head station, passage of the BPD of the IPL, percentage of head after the IPL, circumference of head after IPL were all correlated with the difficulty of OPD. When the distance between the widest diameter of the head and the IPL is < 1.2 cm, there is a 90 % probability of success of OPD. When that distance is > 3.3 cm, there is 90 % probability of cesarean section. When the percentage of head beyond the IPL was > 54 %, there was 90 % probability of successful OPD. DISCUSSION: Translabial ultrasound is useful in the prediction of the difficulty and the success of OPD. The higher the extent of head that passed the IPL, the less difficult the OPD and the greater the success rate of the OPD.

[Fetal-pelvic disproportion and X-ray pelvimetry]. / Disproportion foeto-pelvienne et radiopelvimétrie.

OBJECTIVES: X-ray pelvimetry is a method that not only allows exploring the pelvic inlet but also would partially explain the "fetal-pelvic disproportion". The aims of this study are to estimate this capacity to actually explain the aforementioned disproportion, assessing as well its influence on the follow-up of later pregnancies. PATIENTS AND METHODS: A retrospective study was performed in Angers' hospital, France. We went back over 11 years and included 90 nulliparous patients, all of whom had a C-section due to "fetal-pelvic disproportion". We defined a specific sub-group for arrest of labor. RESULTS: Only 55.5% of the patients had an unfavorable Magnin's index (<23 cm) and 47.8% were, according to it, in the uncertainty - or dystocia - zone. Labor arrest was explained by mechanical obstruction (72% of the patients had pelvic abnormalities) and by dysfunctional patterns (40% due to a posterior position of the occiput, 18% because of hypotonic labor). An important number of elective C-sections (55 cases) was recorded for subsequent pregnancies. Reasons were bound to X-ray pelvimetry (35 cases), the patients' wish (two cases), to maternal pathology (four cases), to a hydramnios (three cases) and to the suspicion of fetal distress (five cases). DISCUSSION AND CONCLUSIONS: The term "fetal-pelvic disproportion" should be carefully used. Some authors used it in case of arrest of labor during two hours, a normal dynamic pattern, sufficient cervical dilation and, for many, an occipoanterior position.

Assessing cephalopelvic disproportion: back to the basics.

Dystocia, or abnormally slow progress in labor, can result from cephalopelvic disproportion (CPD), malposition of the fetal head as it enters the birth canal, or ineffective uterine propulsive forces. Cephalopelvic disproportion occurs when there is mismatch between the size of the fetal head and size of the maternal pelvis, resulting in "failure to progress" in labor for mechanical reasons. Untreated, the consequence is obstructed labor that can endanger the lives of both mother and fetus. Despite the use of imaging technology in an attempt to predict CPD, there is poor correlation between radiologic pelvimetry and the clinical outcome of labor. Clinical pelvimetry still has a place in obstetrics for predicting or confirming CPD, but without appropriate training and repeated practice of this clinical skill, it is in danger of becoming a lost art. For this review, a computerized search of the terms cephalopelvic disproportion, dystocia, pelvimetry, obstructed labor, and malposition was done using MEDLINE, PUBMED, SCOPUS, and CINAHL, and historical articles, texts, articles from indexed journals, and references cited in published works were also reviewed.

Pelvimetry revisited: analyzing cephalopelvic disproportion.

The objective of this study was to assess the clinical value of pelvimetry to predict dystocia due to cephalopelvic disproportion. 63 patients who had received an abdominal CT scan postpartum were included. Pelvimetry was performed retrospectively with these datasets on a 3D workstation; there were no CT examinations performed solely for pelvimetry, and there was no radiation exposure for study purposes. Patients were divided into three groups by the course of birth, i.e. normal vaginal delivery (A), dystocia due to cephalopelvic disproportion (B) and other patients (C). Previously described methods were evaluated for their accuracy in diagnosing cephalopelvic disproportion. The pelvimetric parameters did not show significant differences between groups A (n=20) and B (n=20) except for the sagittal mid-pelvic diameter (q) with 12.7+/-0.6 cm vs. 11.9+/-0.6 cm (p=0.0001). The ROC analysis of the previously described methods showed areas under the curve between 0.50 and 0.67. The ROC curves for q had an area of 0.88, providing 85% sensitivity with 85% specificity. In conclusion, the sagittal mid-pelvic diameter shows potential to detect cephalopelvic disproportion with acceptable accuracy. With the information gained on the CT data, a prospective trial based on MR imaging can be set up to validate the diagnostic accuracy.

Anthropometric measurements in the diagnosis of pelvic size: an analysis of maternal height and shoe size and computed tomography pelvimetric data.

BACKGROUND: To determine whether measurements of maternal height and shoe size are predictors of pelvic size, using erect lateral computerized tomography (CT) pelvimetry as gold standard. MATERIALS AND METHODS: Three hundred and fifty three obstetric patients out of a sequential population of 6112 (5.8%) had CT pelvimetry performed between January 1990 and December 1991 at the Department of Obstetrics and Gynecology, York District Hospital, United Kingdom. Multivariable logistic regression models were built using maternal height (n = 322), shoe size (314) and weight at last clinic visit (n = 318). The reference standard for pelvic size was CT Pelvimetry. Pelvic adequacy was defined as an anterior-posterior diameter of the inlet of > or =11 cm and an anterior-posterior diameter of the outlet > or =10 cm on erect lateral CT pelvimetry. Women with values lower than these were regarded as having an inadequate pelvis. The diagnostic accuracy of the models was determined by the area under the receiver operating characteristic curve (AUC). RESULTS: The area under the curve (AUC) for maternal height (0.768) was not significantly greater than that for shoe size (0.686, p = 0.163 for the difference in AUC's) and weight at the last clinic visit (0.655, p = 0.057 for the difference in the AUCs). The change in the AUC for each of the models (the full model with height, shoe size and weight [0.769]; model for height and shoe size [0.767] model for just height [0.768]) was also not significantly different. CONCLUSIONS: Measurements of maternal height, shoe size and weight at the last clinic visit are not useful for the identification of women with inadequate pelvis.

A narrow pelvic outlet increases the risk for emergency cesarean section.

BACKGROUND: The rate of cesarean section (CS) is increasing in Sweden as well as in most of the industrialized world. One of the most common indications for emergency CS is protracted labor. To what extent fetal pelvic disproportion is a cause of protracted labor is unclear. The value of pelvimetry has been questioned. The purpose of this study was to investigate whether women delivered with emergency CS because of protracted labor had a narrower pelvis than women delivered vaginally did. METHODS: Thirty women delivered with CS because of protracted labor comprised the study group. Thirty women vaginally delivered served as controls. The two groups were matched for gestational age, birth weight, and parity. The study group and the control group underwent an X-ray pelvimetry within 1 month of delivery. RESULTS: The study group and the control group did not differ in maternal age or body mass index. The mean birth weight was 3914 g in the study group and 3884 g in the control group. The mean pelvic outlet was 328 mm in the study group and 346 mm in the control group (P=0.0024). The mean pelvic inlet was 245 mm in the study group and 255 mm in the control group (P=0.0038). CONCLUSION: A narrow pelvic outlet is associated with an increased risk of emergency CS because of protracted labor. A postpartum pelvimetry is recommended and should be used when to decide on route of delivery in forthcoming pregnancies.