Position Of Placenta Research Articles

Early prediction of placenta accreta spectrum by evaluation of risk factors and ultrasound

IntroductionWe explored the predictive utility of clinical risk factors and first-trimester pregnancy ultrasound signs for severe placenta accreta spectrum.Material and methodsPatients with placenta accreta spectrum treated in our institution between March 1, 2017 and December 31, 2022 were analyzed. The patients were divided into those with mild and those with severe conditions. Univariate analysis was used to determine the clinical risk factors and first trimester ultrasound signs associated with severe placenta accreta spectrum. Receiver operating characteristic curves were drawn and the areas under the curves calculated.ResultsUnivariate analysis revealed significant between-group differences between the groups in the number of cesarean sections, scar pregnancy, low gestational sac position, abnormal placental position, focal exophytic mass and abnormal placental lacunae in placental parenchyma (p < 0.05). The number of cesarean sections and first trimester ultrasound signs predicted severe placenta accreta spectrum, with areas under the curves of 0.66 and 0.75. When the number of cesarean sections was combined with low gestational sac position, the placenta position and related ultrasound signs, the areas under the curves for predicting severe placenta accreta spectrum were 0.78, 0.73, and 0.89, respectively.ConclusionsClinical risk factors and first-trimester ultrasound signs predicted severe placental accreta spectrum and their combinations had even greater clinical utility.

Comparison of Placental Location on Ultrasound in Preeclampsia and Normotensive Pregnancy in Third Trimester.

Hypertensive disorders in pregnancy account for 15%-20% maternal and 20%-25% perinatal mortality. There is interest in predicting preeclampsia (PE) early in pregnancy to reduce PE and its subsequent complications. There is no cheap and easily available, reliable predictor for PE. Some studies have shown that the lateral location of placenta is associated with adverse pregnancy outcomes due to PE. The lateral placenta is yet to be proven as a strong predictor of PE to initiate preventive measures. Placental localization can be easily done on routine ultrasonography during pregnancy. In the light of these observations, a prospective study was done to study any association between PE and placental location by ultrasound in third trimester. Research Question: Is there any association between placental location on ultrasound and preeclampsia in third trimester? The objective is to study association between location of placenta and preeclampsia and compare placental location in normotensive pregnancies with that in PE in third trimester. A prospective comparative, case-control, observational study was conducted in the Department of Obstetrics and Gynecology at North DMC Medical College and Hindu Rao Hospital, Delhi, India, from August 2019 to April 2020. The study population included 200 pregnant women with singleton pregnancy in third trimester, without any medical disorders such as diabetes mellitus, hypertension, renal disease, cardiac disease, and coagulation disorder or smoking. One hundred women had preeclampsia and 100 were normotensive controls. Ultrasound was done after filling F form as per the Government of India guidelines to rule out sex determination, and placenta was localized by ultrasound. Placenta was classified as central when it was equally distributed between the right and left sides of the uterus irrespective of anterior, posterior, or fundal position and lateral when 75% or more of the placental mass was on one side of the midline. Placental location was compared in hypertensive and normotensive pregnancies. Out of the total 200 women, 152 (76%) had central and 48 (24%) had lateral placenta. Ninety-two percent of controls and 60% of cases had central placenta. Forty percent of cases and only 8% normotensive women had lateral placenta. Lateral placenta was five times more frequent in presence of PE as compared to normotensive controls. Out of 152 women with central placenta, 92 (60.5%) women were normotensive but with lateral placenta, only 8 (16.7%) had normal blood pressure. PE was present in 83% of women with lateral placenta and in only 39.47% with central placenta. This difference was statistically significant as P < 0.0001 as per Chi-square test. This reflects a significant association between lateral position of placenta and occurrence of PE. As per odds ratio (0.1304) patients without lateral placenta had 90% protection against preeclampsia. Central placenta is more common than lateral placenta. Lateral placenta is seen five times more frequently among hypertensive women and this difference is statistically significant. The absence of lateral placenta provides 90% protection against PE but the severity of PE was not affected by placental location..

Magnetic Resonance Imaging-Based Radiomics Nomogram to Predict Intraoperative Hemorrhage of Placenta Previa.

Placenta previa (PP) is associated with intraoperative and postpartum hemorrhage, increased maternal morbidity and mortality. We aimed to develop a magnetic resonance imaging (MRI)-based nomogram to preoperative prediction of intraoperative hemorrhage (IPH) for PP. A total of 125 PP pregnant women were divided into a training set (n = 80) and a validation set (n = 45). An MRI-based model was built for the classification of patients into IPH and non-IPH groups in a training set and a validation set. Multivariate nomograms were built according to radiomics features. Receiver operating characteristic (ROC) curve was used to assess the model. Predictive accuracy of nomogram were assessed by calibration plots and decision curve analysis. In multivariate analysis, placenta position, placenta thickness, cervical blood sinus, and placental signals in the cervix were significantly independent predictors for IPH (all ps < 0.05). The MRI-based nomogram showed favorable discrimination between IPH and non-IPH groups. The calibration curve showed good agreement between the estimated and the actual probability of IPH. Decision curve analysis also showed a high clinical benefit across a wide range of probability thresholds. Area under the ROC curve was 0.918 (95% confidence interval [CI]: 0.857-0.979) in the training set and 0.866 (95% CI: 0.748-0.985) in the validation set by the combination of four MRI features. The MRI-based nomograms might be a useful tool for the preoperative prediction of IPH outcomes for PP. Our study enables obstetricians to perform adequate preoperative evaluation to reduce blood loss and cesarean hysterectomy. · MRI is an important method for preoperative assessment of the risk of placenta previa.. · MRI-based nomogram can assess the risk of intraoperative bleeding of placenta previa.. · MRI is helpful for more comprehensive evaluation of placenta previa and adequate preoperative preparation..

Feasibility of Non-Gated Dynamic Fetal Cardiac MRI for Identification of Fetal Cardiovascular Anatomy

Introduction: The aim of this study was to evaluate the feasibility of identifying the fetal cardiac and thoracic vascular structures with non-gated dynamic balanced steady-state free precession (SSFP) MRI sequences. Methods: We retrospectively assessed the visibility of cardiovascular anatomy in 60 fetuses without suspicion of congenital heart defect. Non-gated dynamic balanced SSFP sequences were acquired in three anatomic planes of the fetal thorax. The images were analyzed following a segmental approach in consensus reading by an experienced pediatric cardiologist and radiologist. An imaging score was defined by giving one point to each visualized structure, yielding a maximum score of 21 points. Image quality was rated from 0 (poor) to 2 (excellent). The influence of gestational age (GA), field strength, placenta position, and maternal panniculus on image quality and imaging score were tested. Results: 30 scans were performed at 1.5T, 30 at 3T. Heart position, atria, and ventricles could be seen in all 60 fetuses. Basic diagnosis (>12 points) was achieved in 54 cases. The mean imaging score was 16.8+/−3.8. Maternal panniculus (r = −0.3; p = 0.015) and GA (r = 0.6; p < 0.001) correlated with imaging score. Field strength influenced image quality, with 1.5T being better than 3T images (p = 0.012). Imaging score or quality was independent of placenta position. Conclusion: Fetal cardiac MRI with non-gated SSFP sequences enables recognition of basic cardiovascular anatomy.

Placental vessel-guided hybrid framework for fetoscopic mosaicking

ABSTRACT Fetoscopic laser photocoagulation is used to treat twin-to-twin transfusion syndrome; however, this procedure is hindered because of difficulty in visualising the intraoperative surgical environment due to limited surgical field-of-view, unusual placenta position, limited manoeuvrability of the fetoscope and poor visibility due to fluid turbidity and occlusions. Fetoscopic video mosaicking can create an expanded field-of-view image of the fetoscopic intraoperative environment, which could support the surgeons in localising the vascular anastomoses during the fetoscopic procedure. However, classical handcrafted feature matching methods fail on in vivo fetoscopic videos. An existing state-of-the-art method on fetoscopic mosaicking relies on vessel presence and fails when vessels are not present in the view. We propose a vessel-guided hybrid fetoscopic mosaicking framework that mutually benefits from a placental vessel-based registration and a deep learning-based dense matching method to optimise the overall performance. A selection mechanism is implemented based on vessels’ appearance consistency and photometric error minimisation for choosing the best pairwise transformation. Using the extended fetoscopy placenta dataset, we experimentally show the robustness of the proposed framework, over the state-of-the-art methods, even in vessel-free, low-textured, or low illumination non-planar fetoscopic views.

Effect of placenta previa on umbilical cord hematocrit value

Objective Placenta previa is one of the causes of neonatal anemia. This condition is mainly explained by antenatal hemorrhage and incision of the anteriorly located placenta during cesarean section. However, the mechanism of neonatal anemia in placenta previa has not been extensively studied or well elucidated. This study investigates whether placenta previa is associated with lower hematocrit levels in newborns with no antenatal hemorrhage and placental incision. Key findings This prospective study investigated 47 patients with previa and 43 control patients who gave birth with a cesarean section at 34–38 weeks of gestation. Blood samples were obtained from the fetal end of the umbilical vein. The mean umbilical cord hematocrit value was 49.3% in the control patients and 46.7% in the patients with previa, and the difference was statistically significant (p = .029). No significant association was observed between hematocrit value and birth weight, gestational age, newborn gender, placenta position, or preoperative maternal hemoglobin level. Conclusion The study findings reveal that even if not complicated by antepartum or intrapartum hemorrhage, placenta previa may be associated with lower hematocrit values in newborns. Although in none of the cases, the umbilical cord hematocrit value was not as low as to be defined as anemia, this effect of previa on newborns should be considered because of the importance of iron status.

Association between Placenta Accreta and History of Previous C-Section and position of Placenta in Pregnant Women presenting at A Public Sector Hospital of Punjab, Pakistan: a cross-sectional analysis

Background: Placenta accreta is a rare and life threatening disease during pregnancy and causes must be sorted out for its early diagnosis and treatment. Aim: To find the association between placenta accreta and history of previous C-section in pregnant women. Methods: This analytical cross-sectional survey was conducted at Radiology department of DHQ teaching hospital Gujranwala from 1st January, 2022 to 31st March, 2022. A self-administered questionnaire was filled by the pregnant women at the gynecology and obstetrics outdoor department. Data was analyzed by using SPSS-Version 26. Results: AFI and age were found to be normally distributed while all other variables were non-normally distributed. Mean ± S.D of AFI was 10.75 ± 3.99 while mean ± S.D for age were 27.05 ± 3.90. Median ± IQR for gestational age of the study participants was 33.1 ± 8.98. While median ± IQR for body weight and heart rate of the study participants were 2052 ± 1632 and 147 ± 11 respectively. The association of the placenta accreta with history of C-Section was found to be highly statistically significant in our study (P=0.012). Conclusion: It was evident from our study that plecenta accreta was associated with history of C-Section hence the multiparous with history of C-Section should undergo repeated scans for early diagnosis of placenta previa and the patients also need to have a proper follow-up as per consultant’s advice. Key words: C-section, Placenta Accreta, Pregnancy.

Success rate of external cephalic version in relation to the woman's body mass index and other factors-a population-based cohort study.

The aim of this study was to evaluate the impact of women's body mass index (BMI) on the probability of a successful external cephalic version (ECV). A retrospective population-based observational study including all women that underwent an ECV in the southeast region of Sweden from January 2014 to December 2019. Data were collected from electronic medical records, Obstetrix, Cerner. The women were divided into BMI categories according to the World Health Organization classification. Women with a BMI below 25kg/m2 formed the reference group. Crude and adjusted odds ratios for unsuccessful ECV in each BMI group were calculated using binary logistic regression. Furthermore, the association between maternal characteristics and clinical and ultrasound variables at the time of the ECV and unsuccessful ECV was evaluated. A total of 2331 women were included. The overall success rate of ECV was 53.4%. Women with a BMI below 25kg/m2 had a success rate of 51.3% whereas obese women had a success rate of 58.6%. The risk of an unsuccessful ECV among obese women (BMI ≥30kg/m2 ) had an OR of 0.74 (95% CI 0.59-0.94) compared with women with a BMI below 25kg/m2 . After adjusting for suitable confounding factors, the association was no longer significant. Higher maternal age, multiparity, higher gestational age, posterior placenta position, polyhydramnios and higher estimated weight of the fetus at the ECV significantly decreased the risk of an unsuccessful ECV. Maternal obesity does not seem to negatively influence the success rate of ECV. This is a finding that may encourage both caregivers and obese pregnant women to consider an ECV and so avoid a planned cesarean section for breech presentation in this group.

Feasibility of non-gated dynamic fetal cardiac MRI for identification of fetal cardiovascular anatomy

Abstract Funding Acknowledgements Type of funding sources: None. Purpose We sought to retrospectively evaluate the feasibility of identifying the fetal cardiac and thoracic vascular structures with non-gated dynamic balanced steady-state free precession MRI sequences. Methods We retrospectively assessed the visibility of cardiovascular anatomy in 66 fetuses without suspicion of congenital heart defect (mean gestational age 27+/- 4, range 21-38 weeks). Non-gated dynamic balanced steady-state free precession (SSFP) sequences were acquired in three planes (axial, coronal and sagittal) of the fetal thorax (slice thickness 4-5mm, FOV 400, FA 60°, matrix 256x256). The images were analysed following a segmental approach in consensus reading by an experienced paediatric cardiologist and radiologist. An imaging score was defined by giving one point to each visualized structure. Basic diagnostic structures included the atria, ventricles, systemic veins, right and left ventricular outflow tracts (RVOT/LVOT), aortic arch, descending aorta (DAO), ductus arteriosus and thymus (12 points); advanced diagnostic features included the atrioventricular (AV) valves, pulmonary arteries and veins, supraaortic arteries and trachea, yielding a maximum score of 21 points. Image quality was rated from 0 (poor) to 2 (good). The influence of gestational age (GA), field strength, placenta position, and maternal panniculus on image quality and imaging score were tested. Results 34 scans were performed at 1.5 T, 32 at 3 T. Heart position, atria and ventricles could be seen in all 66 fetuses. Basic diagnosis (&amp;gt;12 points) was achieved in 60 (90%) cases, with visualization of the IVC and SVC in 65 (98%) and 63 (95%), RVOT in 62 (94%), LVOT in 61 (92%), aortic arch in 60 (91%), DAO in 64 (97%), ductus arteriosus in 59 (89%) and thymus in 50 (76%) fetuses. The AV valves were recognised in 55 (83%), the pulmonary arteries in 35 (53%), at least one pulmonary vein in 46 (70%), the supraaortic arteries in 42 (64%), and the trachea in 59 (89%) fetuses. The mean imaging score was 16.8 +/- 3.7. Maternal panniculus (r -0.3; p 0.01) and gestational age (r 0.6; p &amp;lt; 0.001) correlated with imaging score. Field strength influenced image quality, with 1.5 T being better than 3T images (p 0.04), but not the total imaging score. Imaging score or quality were independent from placenta position. Conclusions Fetal heart MRI with a non-gated SSFP sequence in multiple planes enables recognition of basic cardiovascular anatomy. Advanced diagnostics may be limited by thick maternal panniculus, lower GA and higher field strength.

Investigating the Association between Placental Site in the Second Trimester of Pregnancy and Pregnancy Outcomes in Mother and Infant: A Retrospective Study

Background: The location of placenta is essential for the proper growth of fetus. This study was conducted to assess the relationship between placental location and perinatal and neonatal outcomes. Materials and Methods: The present retrospective cohort study was carried out on 1000 pregnant women who had delivered in Baqiyatallah Hospital, Tehran, Iran, during 2016-2018. We used a researcher-made questionnaire for collection of clinical and demographic information of patients from their medical records. All women had undergone a detailed ultrasound and Doppler examination at 20–23 weeks. We classified placenta position to four types: Lateral, Posterior, Anterior and Fundal. The data were analyzed using SPSS software version 20.0. Results: Placental site location in 44%, 42.1%, 8.2% and 5.7% of cases were anterior, posterior, lateral and fundal, respectively. The mean birth weight in subjects with lateral and posterior placental site location were 2999.3±643.9, and 3269.7±1776.9 gr as lowest and highest, respectively (p <0.001). Among the newborns in lateral group, 4.88% of them were pre-term, which was significantly higher than other groups (P=0.035). The rate of IUGR birth in lateral group was 4.88% which was higher than other groups (P=0.023). Also, among perinatal outcomes the rate of twin pregnancy was higher in lateral group, while the percentage of female birth in this group was lower than other groups (p <0.001). Conclusion: Lateral placental locations are associated with a number of adverse pregnancy, delivery and infant outcomes. Placental implantation and location at 14 to 24 weeks can be used in the evaluation of pregnancies. In other words, knowing the placenta location can help obstetricians and gynecologists in the better diagnosis of pregnancies at higher risk of complications.

Correlation between Site of Placenta and Umbilical Cord Hematocrit Value

Background: Placenta Previa (PP) is characterized as the unusual implantation of placental tissue over or adjoining the inside cervical os. The commonness of PP is at around 5 for every 1000 pregnancies. It represents roughly 20% of all antepartum drain, front PP was seen as related with unfavorable maternal results including over the top blood misfortune, gigantic transfusion, placenta accreta and hysterectomy. Objective: The purpose of our study was to decide the connection between the site of placenta in pregnant women and the hematocrit (Hct) estimation of umbilical cord blood (CB) of the newborn. Patient and method: This case-control study was carried out at Obstetrics and Gynecology Department, Zagazig University Hospitals and El-Menshawy General Hospital in Tanta during the period from May 2018 to May 2019. The study included 32 pregnant women with various placental site. They were classified into two groups; group 1: women determined to have placenta previa as front or back placenta previa. Group II: women without placenta previa at a similar gestational age as (bunch II). Placenta position was classified as foremost, back and fundal placenta. Results: there was high huge distinction between hemoglobin levels when activity in the placenta previa gathering. Additionally, there was high distinction between the placenta previa gathering and the control group in respect to fetal haematocrit esteem, which was higher among placenta previa gathering. Regarding fetal hematocrit and placenta site, our examination demonstrated that there was high solid critical connection between the placental site and haematocrit esteem. Conclusion: Placental area can decide pregnancy outcome.

Standardization of diagnosis for coiling of the umbilical cord around fetal neck by ultrasound.

To elucidate classification of coiling of the umbilical cord around fetal neck (CUFN) by ultrasound and forming factors of entanglement angle of CUFN. From January 2006 to December 2012, color Doppler ultrasonic was used to observe the blood flow vector of umbilical artery, and prospective descriptive observation was made for entanglement direction and type of 707 single fetuses taking prenatal examination in our hospital during the middle and late trimester of pregnancy and having umbilical cord echo around the neck. The relationship of position of fetus, position of placenta and entanglement direction of umbilical cord with the entanglement angle of umbilical cord is analyzed. Among the 707 fetuses, 634 had one circle of coiling, 43 had two circles of coiling, two had three circles of coiling, and 28 had CUFN. According to entanglement direction, 361 had entanglement from left to right and 318 had entanglement from right to left According to entanglement type, 305 were C-shaped type (43.14%), 85 were O-shaped type (12.02%), 289 were α-shaped type (40.88%), and 28 were L-shaped type (3.96%). Color Doppler ultrasound was used to detect the entanglement direction of umbilical cord and establish the five-type classification of umbilical cord around the neck, laying the foundation for the feasibility of establishing the normalization of diagnostic standard of umbilical cord around the neck.

A preliminary study of fetal intelligent navigation echocardiography in the normal fetuses during second and third trimester

Objective To investigate the value of fetal intelligent navigation echocardiography (FINE, 5D Heart) in displaying the normal fetal heart structure during 20 to 38 weeks′ gestation. Methods Three-dimensional data of fetal heart during 20 to 38 weeks′ gestation were acquired using volume transducer prospectively. The STIC volume images were post-processed with 5D heart software by three physicians with different levels of echocardiographic examination and the quality of the section images were analyzed. The intra- and interobserver repeatability was analyzed for the qualification of section images. The correlation between the quality of image and gestational age, body mass index, the placenta position, fetal initial plane position were evaluated using univariate and multivariable logistic regression analysis. Results Two hundreds and five cases of pregnant women were included, and 9 cases were excluded.Volume data acquisition was completed in 180 pregnant women, and the image acquisition rate was 91.8%. The data were assessed twice by three observers and qualified 9 section images were gotten in 156-180 cases (degree of qualification 86.7%-100%). The screening images were satisfied in 152 cases (84.4%), dissatisfied with 28 cases (15.6%). The intra-observer agreement by three observers was absolute concord in four chamber view and abdomen/stomach view; excellent in three vessel trachea view(3VT), five chamber view, left ventricular outflow tract view and superior and inferior vena cava view; good in right ventricular outflow tract view, ductal arch view and aortic arch view. The inter-observer agreement by each of three observers was absolute concord in four chamber view and abdomen/stomach view; excellent in superior and inferior vena cava view; excellent to good in five chamber view, left ventricular outflow tract view, right ventricular outflow tract view; good in 3VT, ductal arch view and aortic arch view. In a univariate analysis, the quality of the image was associated with obesity (χ2=15.338, P=0.000), gestational age (χ2=23.356, P=0.000). Multivariable analysis showed that the obesity (OR=5.587, P=0.001) and gestational age (OR=8.843, P=0.000) were factors affecting the quality of the image. The average time spent in post-processing the images for first time by three observers was (2.77±1.39)min, and there was no significant difference among observers (P>0.05). Conclusions Fetal intelligent navigation echocardiography (FINE, 5D Heart) based on STIC volumes can successfully generate 9 standard fetal echocardiography views in 86.7%-100% of fetuses in the 2nd and 3rd trimesters. This method can simplify examination of the fetal heart and reduce operator dependency. Key words: Echocardiography; Fetal heart; Spatiotemporal image correlation; Fetal intelligent navigation echocardiography(FINE)

Étude de la faisabilité et de la valorisation de l’échographie focalisée dans un cadre d’explorations fonctionnelles extra-hospitalières pour des grossesses à risque

To assess the clinical, legal, and technical roles of ultrasound in an outpatient pregnancy assessment clinic, while evaluating the feasibility for these consultations to be performed at home. We prospectively assessed all consultations from April 3to May 31, 2013, at the outpatient pregnancy assessment clinic of La Pitié-Salpêtrière, Paris, France. We recorded all procedures and the number and type of ultrasound examination performed, according to their indication. For each consultation, we evaluated whether the routine protocols were sufficient or if the attending obstetrician was asked for advice. Finally, we asked the patients if they would prefer having this consultation in a home-care setting. We recorded 429consultations (n) for 234patients (Np). Indications were diabetes (n=106/Np=59), assessment of fetal growth (n=90/Np=43), another single indication (n=106/Np=59), multiple indications (n=46/Np=12), term pregnancies (n=39/Np=30), and a history of abnormal pregnancy (n=27/Np=10). CTG was performed for 91% of consultations, blood samples for 10%, and ultrasound for 88%, which included amniotic fluid evaluation (79%), umbilical Doppler (69%), fetal biometries (36%), uterine artery Doppler (0.7%), cervical length (2%), suspicion of breech presentation (4%) and placenta position (0.7%). Most of these ultrasound examinations could not be financially value if performed by a midwife. Routine protocols were sufficient for the management of 68% of these consultations, 26% required the attending obstetrician, and 6% were finally low-risk. Performing these consultations in a home-care setting was medically possible and requested by the patient for 16% of consultations (6% of patients). These are encouraging results to experiment the outpatient pregnancy assessment clinic in a home-care setting, although the financial valorization system in France is poorly adapted.

Ultrasonographic Study of Placenta Positioning and Its Significance in Parturition among Women in Delta State

Ultrasound is a useful adjunct to the physical examination, particularly in obstetrics patients. By ultrasonography we visualize the placenta position in-situ and describe various positioning of placenta in the uterus. The placenta is positioned at different sites in the uterus which can predict methods of parturition. The objective of this study is to investigate the different positions of placenta as seen in ultrasound scan and it's significant in parturition among women in Delta state. The study comprises of 150 women who registered for antenatal care at Eku Baptist Hospital Eku, Delta state, and have given birth in the Hospital. The pregnant women were examined with ultrasound scan which determined the positions of the placenta at the radiodiagnostic department. The different positions such as anterior, posterior, fundal and previa were recorded. The methods of deliveries were also taken note of in the pre-maternal labour forms in obstetrics/gynaecology department and health record office of the Hospital. Data were presented as mean and standard deviation; data were analysed using statistical package for social science (SPSS). The cases of previa were related to the type of delivery out of 28 cases of previa 18 women delivered by caesarean section and 10 had normal delivery. 10 out of all are previa type I, 7 are previa type II, and 11 are previa type III. All type III cases delivered through caesarean section.

Investigating the possible role of placenta position in road accident consecutive foetal loss

The main objective of this study is to evaluate the possibility of using a numerical model of a pregnant woman to understand placenta injury mechanisms in car accident situations. As a first step, a finite element (FE) model was developed by adding a gravid uterus in the already available Radioss Humos® full human body model. This numerical model was evaluated using a cadaver tests approach. Simulated and experimental gravid uterus kinematics were compared and found in good agreement. Indentation tests also were performed on fresh placenta specimens. A placenta FE segment was then implemented into the full pregnant body model at different locations. For a simulated frontal impact at moderate speed, the placenta position was not found to significantly influence the abruption risk. Our results illustrate the potential of numerical simulation to improve the description of injury mechanisms related to pregnant women, in particular the placenta abruption. Further work is, however, required to develop the experimental tests database used for the model validation, and to investigate sensibility to maternal morphology.

Does placenta position modify the risk of placental abruption in car crashes?

The goal of this paper is to study the influence of placenta position on the risk of placenta abruption following a car crash involving a full term pregnant woman in the driver's seat. We developed an anatomically precise finite element numerical model of a pregnant woman. This numerical model was validated using experimental data from crash tests using cadavers given to science. For a frontal impact at a speed of 20 km/h, the mean value of peak strain levels at the utero-placenta interface were found to be close to 20%, independent of placenta position, representing an adverse foetal outcome risk of approximately 15%. This study found no significant effect of placenta position on the risk of placenta abruption. Our anatomically precise approach does however confirm the interest of using a numerical model when studying injury mechanisms in pregnant women involved in car crashes.

Systematic Floral Anatomy of Pontederiaceae

Twenty species of Pontederiaceae and six species of the outgroup families Haemodoraceae and Philydraceae were investigated with regard to floral anatomy, using standard histological methods and graphic reconstructions. Variation is described in several features, including functional carpel number, the distribution of floral aerenchyma, the presence of unusual floral epithelial cells, the presence, type, and distribution of tannin cells, crystal type and distribution, aspects of placentation, ovule number, number of ovule rows per carpel, and septal nectary presence. In order to better assess character homology, one of these features, placentation, was divided into three discrete characters: septal fusion, placenta position, and placenta evagination. Several of the floral characters were optimized onto a most parsimonious cladogram from a relatively recent study using combined chloroplast DNA data. Associations of character states with specific clades were observed in functional carpel number, aerenchyma distribution, epithelial cell presence, tannin cell distribution, septal nectary presence, and the three redefined aspects of placentation: septal fusion, placenta position, and placenta evagination. These floral data will be valuable in further elucidating relationships in Pontederiaceae in future studies of the group.

Does the use of a tocolytic agent affect the success rate of external cephalic version?

OBJECTIVE: Our purpose was to study the effect of ritodrine tocolysis on the success rate of external cephalic version at ≥36 weeks' gestation. STUDY DESIGN: This was a prospective, double-blinded, randomized study. All patients were at ≥36 weeks' gestation, confirmed by early ultrasonography. External cephalic version assessment included nonstress testing before and after external cephalic version and ultrasonographic evaluation of type of breech, estimated fetal weight, position of placenta and fetal spine, and amniotic fluid index. Patients were excluded if the breech was not mobile or if they had any contraindications to tocolysis or external cephalic version. After randomization 283 patients received either ritodrine (111 μg/min) or identical placebo by intravenous infusion for ≥20 minutes. Up to three attempts at external cephalic version under ultrasonographic surveillance were performed. With an α error of 0.05 and a β of 0.2, 264 patients were required to complete this study. RESULTS: There were no differences between study groups in maternal age, body mass index, gestational age, amniotic fluid index, position of fetal spine, and placental location. Statistical analysis controlled for parity because parity had a major influence on success rates. There was a higher success rate in the group receiving ritodrine tocolysis (52% vs 42%, p = 0.028). Ritodrine improved success rates in nulliparous patients (43% vs 25%, p = 0.026) but not in parous subjects (66% vs 58%, p = 0.385). CONCLUSION: Ritodrine tocolysis improves the success rate of external cephalic version performed at ≥36 weeks in nulliparous patients. (Am J Obstet Gynecol 1996;175:859-61.)

Early detection of heart action in the fetus and determination of placenta position with the Doppler ultrasonic method.

1. An ultrasonic examination with apparatus based on the Doppler effect will under certain conditions make it possible to detect the fetal heartbeat beginning with the 7th to 8th week of pregnancy. When a pregnancy is over 13 weeks, the life or death of a fetus is established with certainty. 2. The rate of a fetal heartbeat at an early stage of a pregnancy is usually between 140 and 160 per minute. 3. An ultrasonic examination makes it possible to determine whether there is a heartbeat when a miscarriage is threatened, and when an undeveloped pregnancy is suspected, thus enabling a doctor to take the proper steps. 4. The Doppler ultrasonic method is rapid, simple, and sufficiently accurate to determine the position of the placenta. 5. An ultrasonic examination takes from 1 to 3 min, requires no special preparation of the women, evokes no unpleasant sensations in the examinee, and has no effect on the future development of the fetus.