Fetal Head Research Articles

Dystocia due to lateral deviation of foetal head and its management in a Punganur cattle

Dystocia due to lateral deviation of head and neck is one of the most common types of ruminant dystocia. In one such case, a 7-year- old Punganur cow was reported and successfully managed. The cow was straining and showing symptoms of labor pain and respiratory distress. The cervix was fully dilated, and the birth passage was dry. Foetus was in anterior presentation, dorso-sacral position with extreme left deviation of head and neck. When attempts made by extraction to expel out the foetus, Punganur calf was delivered. The cow was provided with proper postoperative care and management to facilitate the recovery of the uterus and restore normal functioning.

Prediction of large-for-gestational-age at birth using fetal biometry in type 1 and type 2 diabetes: A retrospective cohort study.

To compare ultrasound-assessed fetal head circumference (HC), abdominal circumference (AC), HC/AC ratio, and estimated fetal weight (EFW) in prediction of large-for-gestational-age (LGA) at birth in pregnancies affected by type 1 (T1DM) and type 2 (T2DM) diabetes. This retrospective cohort study included all women with T1DM and T2DM giving birth to singletons between 2010 and 2019 at Aalborg University Hospital, Denmark. Ultrasound scans were performed at 16, 20, 28 and 34 weeks of pregnancy. LGA was defined as birth weight deviation of 15% or greater from the expected for gestational age (≥90th centile). Prediction of LGA was assessed by logistic regression adjusted for maternal characteristics and glycated hemoglobin (HbA1c) and area under the receiver operating characteristics curve (AUC). Among 180 T1DM pregnancies, 118 (66%) had an LGA neonate at birth. At 28 weeks of pregnancy, they were predicted with AUCHC/AC = 0.67, AUCAC = 0.85, and AUCEFW = 0.86. The multivariate analysis did not improve the predictive performance of the HC/AC ratio or AC. Among 87 T2DM pregnancies, 36 (41%) had an LGA neonate at birth. At 28 weeks, they were predicted with AUCHC/AC = 0.73, AUCAC = 0.83, and AUCEFW = 0.87. In T2DM, the multivariate analysis significantly improved the predictive performance for both HC/AC ratio and AC from 20 weeks of pregnancy. In T1DM and T2DM pregnancies, LGA is characterized by a general fetal overgrowth including both AC and HC. Therefore, AC and EFW perform better than the HC/AC ratio in the prediction of LGA. In T2DM, as opposed to T1DM, the predictive performance was improved by the inclusion of maternal characteristics and HbA1c in the analysis.

Outcomes and factors influencing the second stage of labour in singleton deliveries

Objective: To define the characteristics of the second stage of labour and the outcomes of labour. Study design: The study includes 725 cases of pregnant monitored during the second stage of labour at the Obstetrics Centers of Hue Central Hospital and the Hue University of Medicine and Pharmacy Hospital from January 2022 to August 2023. Inclusion criteria: Singleton pregnancy, cephalic presentation, gestational age between 37 and 41 weeks 6 days, height ≥ 145 cm. Exclusion criteria: Category 2 and 3 cardiotocography (CTG) during the first stage of labour, refusal to participate in the study. Methodology is a cross-sectional descriptive study with a convenient sample size. Results: The average duration of the second stage was 51.73 ± 22.55 minutes. The mean duration for vaginal deliveries was 46.45 ± 16.27 minutes, instrumental deliveries were 48.89 ± 22.65 minutes, and cesarean sections were 59.86 ± 28.75 minutes (p < 0.05). Vaginal deliveries constituted 87.5%, cesarean sections 10.4%, and instrumental deliveries 2.2%. Non-engagement of the fetal head in the second stage was associated with a 19.5 higher risk of instrumental or cesarean delivery compared to engaged presentations (p < 0.05). Occurrence of transverse or posterior positions had a 6.4 higher intervention rate for instrumental or cesarean deliveries than anterior positions (p < 0.05). Less than 3 contractions during the second stage increased the risk of cesarean or instrumental delivery by 5.5 times compared to those with ≥ 3 contractions (p < 0.05). Key words: Second stage of labour, cesarean delivery, instrumental delivery, fetal presentation.

A national survey of clinicians’ opinions of rotational vaginal births

IntroductionMalposition of the fetal head, defined as occiput transverse or posterior positions, occurs in approximately 5% of births. At full cervical dilatation, fetal malposition is associated with an increased risk of rotational vaginal birth. There are three different rotational methods: manual rotation, rotational ventouse or rotational (Kielland’s) forceps. In the absence of robust evidence, it is not currently known which of the three methods is most efficacious, and safest for parents and babies. ObjectiveTo gain greater insights into opinions and preferences of rotational birth to explore the acceptability and feasibility of performing a randomised trial comparing different rotational methods. Material and methodsA survey was sent via email to obstetricians from the British Maternal Fetal Medicine Society, as well as expert obstetricians and active academics in ongoing research in the UK. The questions focussed on perceived competence, preferred rotational method, location (theatre or labour room), willingness to recruit to an RCT, and its outcome measures. Closed questions were followed by the option of free text to allow further comments. The free text answers underwent thematic analysis. Results252 consultant obstetricians responded. The majority stated they were competent in performing manual rotation (88.1%). Half felt proficient using Kielland’s rotational forceps (54.4%). Most obstetricians felt skilled in rotational ventouse (76.2%). Manual rotation was the preferred first rotational method of choice in cases of both occiput transverse and posterior positions. The decision for which rotational method to attempt first was considered case-dependent by many. Two thirds of obstetricians would usually conduct rotational births in theatre (67.9%). Over half (52%) do not routinely use intrapartum ultrasound. Most (62.7%) would be willing to recruit to a randomised controlled trial comparing manual versus instrumental rotation. Over half (57.2%) would be willing to recruit to the same RCT if they were the most senior doctor competent in rotational vaginal birth supervising a junior. ConclusionThere is a wide range of practice in conducting rotational vaginal births in the UK. An RCT to investigate the impact of different rotational methods on outcome would be both feasible and desirable, especially in research-active hospitals.

Obstetrical Constraints and the Origin of Extended Postnatal Brain Maturation in Hominin Evolution.

The origin of difficult birth is still a matter of debate in obstetrics. Recent studies hypothesized that early hominins already experienced obstructed labor even with reduced neonatal head sizes. The aim of this work is to test this hypothesis using an extant obstetrical sample with known delivery outcomes. Three delivery outcomes (i.e., instrument-assisted, Caesarean section, and vaginal birth) were evaluated using a discriminant analysis based on 131 mother-baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine "dyads" generated from the combination of six pelvic reconstructions (three for Australopithecus afarensis, two for A. africanus, and one for A. sediba) and three fetal head size estimations. The obstetrical analysis revealed that dystocic births can be predicted by pelvic features such as an anteroposteriorly flattened pelvic inlet. Australopithecines shared these pelvic morphologies with humans and had eutocic birth only for infants of 110 g brain size or smaller, equaling a human-like neonatal/adult brain size ratio of 25-28%. Although birth mechanism cannot be deduced, the newborn/adult brain size ratio was likely more human-like than previously thought, suggesting that australopithecines were secondarily altricial to circumvent instances of obstructed labor and subsequently require a prolonged postnatal brain growth period, implying some aspects of life history pattern similar to modern humans.

Shoulder Dystocia: A Comprehensive Literature Review on Diagnosis, Prevention, Complications, Prognosis, and Management.

The term dystocia refers to labor characterized by a slow progression with delayed rates or even pauses in the dilation of the cervix or the descent of the fetus. Dystocia describes the deviation from the limits that define a normal birth and is often used as a synonym for the term pathological birth. Shoulder dystocia, also known as the manual exit of the shoulders during vaginal delivery on cephalic presentation, is defined as the "failure of the shoulders to spontaneously traverse the pelvis after delivery of the fetal head". This means that obstetric interventions are necessary to deliver the fetus's body after the head has been delivered, as gentle traction has failed. Abnormal labor (dystocia) is expressed and represented in partograms or by the prolongation of the latent phase or by slowing and pausing in the phases of cervical dilatation and fetal descent. While partograms are helpful in visualizing the progress of labor, regular use of them has not been shown to enhance obstetric outcomes considerably, and no partogram has been shown to be superior to others in comparative trials. Dystocia can, therefore, appear in any phase of the evolution of childbirth, so it is necessary to simultaneously assess all the factors that may contribute to its abnormal evolution, that is, the forces exerted, the weight, the shape, the presentation and position of the fetus, the integrity and morphology of the pelvis, and its relation to the fetus. When this complication occurs, it can result in an increased incidence of maternal morbidity, as well as an increased incidence of neonatal morbidity and mortality. Although several risk factors are associated with shoulder dystocia, it has proven impossible to recognize individual cases of shoulder dystocia in practice before they occur during labor. Various guidelines have been published for the management of shoulder dystocia, with the primary goal of educating the obstetrician and midwife on the importance of a preplanned sequence of maneuvers, thereby reducing maternal and neonatal morbidity and mortality.

Retraction: Management of Impacted Fetal Head at Caesarean Birth.

K. Cornthwaite, R. Bahl, C. Winter, Wright, J. Kingdom, K. Walker, G. Tydeman, A. Briley, M. Schmidt-Hansen, T. Draycott, and the Royal College of Obstetricians & Gynaecologists. Management of Impacted Fetal Head at Caesarean Birth. BJOG. 2023;130(12):e40-e64, https://doi.org/10.1111/1471-0528.17534. The above article, published on June 12, 2023, in Wiley Online Library (Wiley Online Library), has been retracted by agreement between the authors, journal Editor-in-Chief, Aris Papageorghiou, the Royal College of Obstetricians and Gynaecologists, and John Wiley & Sons Ltd. The retraction has been agreed following the retraction of (1), a key paper cited in the above article. The retraction of (1) notes concerns regarding discrepancies between the retrospective trial registration and the published article. In light of this, the Royal College of Obstetricians & Gynaecologists has determined that the data and subsequent results in the above article are now implicated due to the discrepancies found in (1), particularly regarding the benefits of Fetal Pillow in relation to both maternal and neonatal outcomes. Reference: (1) S.L. Seal, A. Dey, S.C. Barman, G. Kamilya, J. Mukherji, and J.L. Onwude, Retracted: "Randomized controlled trial of elevation of the fetal head with a fetal pillow during cesarean delivery at full cervical dilatation," International Journal of Gynecology & Obstetrics 133, no. 2 (2016): 178-182, https://doi.org/10.1016/j.ijgo.2015.09.019.

FetalBrainAwareNet: Bridging GANs with anatomical insight for fetal ultrasound brain plane synthesis

Over the past decade, deep-learning (DL) algorithms have become a promising tool to aid clinicians in identifying fetal head standard planes (FHSPs) during ultrasound (US) examination. However, the adoption of these algorithms in clinical settings is still hindered by the lack of large annotated datasets. To overcome this barrier, we introduce FetalBrainAwareNet, an innovative framework designed to synthesize anatomically accurate images of FHSPs. FetalBrainAwareNet introduces a cutting-edge approach that utilizes class activation maps as a prior in its conditional adversarial training process. This approach fosters the presence of the specific anatomical landmarks in the synthesized images. Additionally, we investigate specialized regularization terms within the adversarial training loss function to control the morphology of the fetal skull and foster the differentiation between the standard planes, ensuring that the synthetic images faithfully represent real US scans in both structure and overall appearance. The versatility of our FetalBrainAwareNet framework is highlighted by its ability to generate high-quality images of three predominant FHSPs using a singular, integrated framework. Quantitative (Fréchet inception distance of 88.52) and qualitative (t-SNE) results suggest that our framework generates US images with greater variability compared to state-of-the-art methods. By using the synthetic images generated with our framework, we increase the accuracy of FHSP classifiers by 3.2% compared to training the same classifiers solely with real acquisitions. These achievements suggest that using our synthetic images to increase the training set could provide benefits to enhance the performance of DL algorithms for FHSPs classification that could be integrated in real clinical scenarios.

A Comprehensive Review of the Research Literature on External Cephalic Version (ECV)

External cephalic version (ECV) is an approach to turning a fetus from the breech presentation by external maneuvering of the fetus through the maternal abdominal wall into a cephalic presentation. We conducted a systematic search of the current literature on ECV to provide a comprehensive overview of the procedure and associated success rates, risks, and alternatives to ECV. Tocolytics can improve ECV success, but none of the tocolytics shown to be effective for ECV are currently available in Canada. The factors that can best predict ECV success are low uterine tone (associated with parity or tocolytics), easy palpation of the fetal head, and an unengaged breech. The most common side effect of ECV is transient fetal bradycardia with an incidence of one to six percent of all ECV procedures. The risk of requiring an emergency caesarean section because of ECV appears to be around 0.5% or one in 200 ECV procedures performed. Our review suggested no significant risk of fetal/neonatal mortality or serious morbidity associated with ECV. Few alternative approaches to turning a fetus in the breech presentation have been adequately studied. ECV should be considered for all women with a fetus in the breech presentation at term in the absence of any contraindications to the procedure.

Development of a 3D-printed nuchal translucency model: a pilot study for prenatal ultrasound training

BackgroundWe used two 3D ultrasound volumes of fetal heads at 13 weeks to create live-size 3D-printed phantoms with a view to training or assessment of diagnostic abilities for normal and abnormal nuchal translucency measurements. The phantoms are suitable for use in a water bath, imitating a real-life exam. They were then used to study measurement accuracy and reproducibility in examiners of different skill levels.MethodsUltrasound scans of a 13 + 0-week fetus were processed using 3D Slicer software, producing a stereolithography file for 3D printing. The model, crafted in Autodesk Fusion360™, adhered to FMF guidelines for NT dimensions (NT 2.3 mm). Additionally, a model with pathologic NT was designed (NT 4.2 mm). Printing was performed via Formlabs Form 3® printer using High Temp Resin V2. The externally identical looking 3D models were embedded in water-filled condoms for ultrasound examination. Eight specialists of varying expertise levels conducted five NT measurements for each model, classifying them in physiological and abnormal models.ResultsClassification of the models in physiological or abnormal NT resulted in a detection rate of 100%. Average measurements for the normal NT model and the increased NT model were 2.27 mm (SD ± 0.38) and 4.165 mm (SD ± 0.51), respectively. The interrater reliability was calculated via the intraclass correlation coefficient (ICC) which yielded a result of 0.883, indicating robust agreement between the raters. Cost-effectiveness analysis demonstrated the economical nature of the 3D printing process.DiscussionThis study underscores the potential of 3D printed fetal models for enhancing ultrasound training through high inter-rater reliability, consistency across different expert levels, and cost-effectiveness. Limitations, including population variability and direct translation to clinical outcomes, warrant further exploration. The study contributes to ongoing discussions on integrating innovative technologies into medical education, offering a practical and economical method to acquire, refine and revise diagnostic skills in prenatal ultrasound. Future research should explore broader applications and long-term economic implications, paving the way for transformative advancements in medical training and practice.

Management of impacted fetal head at cesarean birth: A systematic review and meta-analysis.

Despite increasing incidence of impacted fetal head at cesarean birth and associated injury, it is unclear which techniques are most effective for prevention and management. A high quality evidence review in accordance with international reporting standards is currently lacking. To address this gap, we aimed to identify, assess, and synthesize studies comparing techniques to prevent or manage impacted fetal head at cesarean birth prior to or at full cervical dilatation. We searched MEDLINE, Emcare, Embase and Cochrane databases up to 1 January 2023 (PROSPERO: CRD420212750016). Included were randomized controlled trials (any size) and non-randomized comparative studies (n ≥ 30 in each arm) comparing techniques or adjunctive measures to prevent or manage impacted fetal head at cesarean birth. Following screening and data extraction, we assessed risk of bias for individual studies using RoB2 and ROBINS-I, and certainty of evidence using GRADE. We synthesized data using meta-analysis where appropriate, including sensitivity analyses excluding data published in potential predatory journals or at risk of retraction. We identified 24 eligible studies (11 randomized and 13 non-randomized) including 3558 women, that compared vaginal disimpaction, reverse breech extraction, the Patwardhan method and/or the Fetal Pillow®. GRADE certainty of evidence was low or very low for all 96 outcomes across seven reported comparisons. Pooled analysis mostly showed no or equivocal differences in outcomes across comparisons of techniques. Although some maternal outcomes suggested differences between techniques (eg risk ratio of 3.41 [95% CI: 2.50-4.66] for uterine incision extension with vaginal disimpaction vs. reverse breech extraction), these were based on unreliable pooled estimates given very low GRADE certainty and, in some cases, additional risk of bias introduced by data published in potential predatory journals or at risk of retraction. The current weaknesses in the evidence base mean that no firm recommendations can be made about the superiority of any one impacted fetal head technique over another, indicating that high quality training is needed across the range of techniques. Future studies to improve the evidence base are urgently required, using a standard definition of impacted fetal head, agreed maternal and neonatal outcome sets for impacted fetal head, and internationally recommended reporting standards.

Localization of Catecholaminergic Neurofibers in Pregnant Cervix as a Possible Myometrial Pacemaker.

In eutocic labor, the autonomic nervous system is dominated by the parasympathetic system, which ensures optimal blood flow to the uterus and placenta. This study is focused on the detection of the quantitative presence of catecholamine (C) neurofibers in the internal uterine orifice (IUO) and in the lower uterine segment (LUS) of the pregnant uterus, which could play a role in labor and delivery. A total of 102 women were enrolled before their submission to a scheduled cesarean section (CS); patients showed a singleton fetus in a cephalic presentation outside labor. During CS, surgeons sampled two serial consecutive full-thickness sections 5 mm in depth (including the myometrial layer) on the LUS and two randomly selected samples of 5 mm depth from the IUO of the cervix. All histological samples were studied to quantify the distribution of A nerve fibers. The authors demonstrated a significant and notably higher concentration of A fibers in the IUO (46 ± 4.8) than in the LUS (21 ± 2.6), showing that the pregnant cervix has a greater concentration of A neurofibers than the at-term LUS. Pregnant women's mechanosensitive pacemakers can operate normally when the body is in a physiological state, which permits normal uterine contractions and eutocic delivery. The increased frequency of C neurofibers in the cervix may influence the smooth muscle cell bundles' activation, which could cause an aberrant mechano-sensitive pacemaker activation-deactivation cycle. Stressful circumstances (anxiety, tension, fetal head position) cause the sympathetic nervous system to become more active, working through these nerve fibers in the gravid cervix. They might interfere with the mechano-sensitive pacemakers, slowing down the uterine contractions and cervix ripening, which could result in dystocic labor.

Which type of forceps is better for nonrotational operative births? A simulation study comparing Thierry spatulas and Simpson-Braun and Kielland forceps.

Obstetric forceps play an important role in safe childbirth, yet there is a lack of distinction between various forceps types in clinical practice. This study aimed to evaluate and compare perineal pressure and forces on the baby during nonrotational forceps-assisted births using Simpson-Braun forceps, Kielland forceps, and Thierry spatulas on a simulation model. This experimental study involved six obstetricians conducting 108 forceps-assisted births on a simulation model. Instruments were assessed for their impact on perineal pressure, traction force, and operator-assessed difficulty. Thierry's spatulas exerted the lowest force on the baby, while Kielland forceps exhibited the lowest perineal pressure, though not statistically significant. An experienced obstetrician demonstrated less perineal pressure with Simpson forceps. Notably, no significant differences in difficulty were observed between instruments. This study highlights distinctions in forceps performance, with Thierry spatulas applying the least force on the fetal head, while an experienced obstetrician fared better with Simpson forceps in terms of perineal pressure. Kielland forceps remain a viable alternative for nonrotational forceps births, showing comparable outcomes.

Management of fetal head and neck masses: Evaluation of prenatal factors associated with airway obstruction and decision for definitive airway and ex-utero intrapartum treatment at birth.

Fetal head and neck masses can result in critical airway obstruction. Our study aimed to evaluate prenatal factors associated with the decision for a definitive airway, including ex-utero intrapartum treatment (EXIT), at birth among at-risk fetuses. A single-institution retrospective review evaluated all fetal head and neck masses prenatally diagnosed from 2005 to 2023. The primary outcome was the decision for a definitive airway at birth, including intubation, tracheostomy, or EXIT. Thirty four patients were included, with 23 deliveries occurring at our institution. 8/23 (35%) patients received a definitive airway at birth, six underwent an EXIT procedure, and two required intubation only. Patients who received a definitive airway had higher rates of polyhydramnios (50% vs. 7%, p=0.03), tracheal narrowing on ultrasound (US) (50% vs. 0%, p=0.01), tracheal displacement on US (63% vs. 0%, p<0.01), abnormal fetal breathing on US (50% vs. 0%, p=0.01), tracheal narrowing or displacement on magnetic resonance imaging (MRI) (75% vs. 7%, p<0.01), and larger mass maximum diameter (7.9 vs. 4.3cm, p=0.02). In our series, 100% of patients with polyhydramnios, tracheal narrowing or displacement on either US or MRI, and abnormal fetal breathing on US received a definitive airway at birth. Prenatal findings of tracheal narrowing or displacement, polyhydramnios, and abnormal fetal breathing are strongly associated with the decision for a definitive airway at birth and warrant mobilization of appropriate resources.

PSFHSP-Net: an efficient lightweight network for identifying pubic symphysis-fetal head standard plane from intrapartum ultrasound images

The accurate selection of the ultrasound plane for the fetal head and pubic symphysis is critical for precisely measuring the angle of progression. The traditional method depends heavily on sonographers manually selecting the imaging plane. This process is not only time-intensive and laborious but also prone to variability based on the clinicians’ expertise. Consequently, there is a significant need for an automated method driven by artificial intelligence. To enhance the efficiency and accuracy of identifying the pubic symphysis-fetal head standard plane (PSFHSP), we proposed a streamlined neural network, PSFHSP-Net, based on a modified version of ResNet-18. This network comprises a single convolutional layer and three residual blocks designed to mitigate noise interference and bolster feature extraction capabilities. The model’s adaptability was further refined by expanding the shared feature layer into task-specific layers. We assessed its performance against both traditional heavyweight and other lightweight models by evaluating metrics such as F1-score, accuracy (ACC), recall, precision, area under the ROC curve (AUC), model parameter count, and frames per second (FPS). The PSFHSP-Net recorded an ACC of 0.8995, an F1-score of 0.9075, a recall of 0.9191, and a precision of 0.9022. This model surpassed other heavyweight and lightweight models in these metrics. Notably, it featured the smallest model size (1.48 MB) and the highest processing speed (65.7909 FPS), meeting the real-time processing criterion of over 24 images per second. While the AUC of our model was 0.930, slightly lower than that of ResNet34 (0.935), it showed a marked improvement over ResNet-18 in testing, with increases in ACC and F1-score of 0.0435 and 0.0306, respectively. However, precision saw a slight decrease from 0.9184 to 0.9022, a reduction of 0.0162. Despite these trade-offs, the compression of the model significantly reduced its size from 42.64 to 1.48 MB and increased its inference speed by 4.4753 to 65.7909 FPS. The results confirm that the PSFHSP-Net is capable of swiftly and effectively identifying the PSFHSP, thereby facilitating accurate measurements of the angle of progression. This development represents a significant advancement in automating fetal imaging analysis, promising enhanced consistency and reduced operator dependency in clinical settings.Graphical abstract

PSFHS: Intrapartum ultrasound image dataset for AI-based segmentation of pubic symphysis and fetal head

During the process of labor, the intrapartum transperineal ultrasound examination serves as a valuable tool, allowing direct observation of the relative positional relationship between the pubic symphysis and fetal head (PSFH). Accurate assessment of fetal head descent and the prediction of the most suitable mode of delivery heavily rely on this relationship. However, achieving an objective and quantitative interpretation of the ultrasound images necessitates precise PSFH segmentation (PSFHS), a task that is both time-consuming and demanding. Integrating the potential of artificial intelligence (AI) in the field of medical ultrasound image segmentation, the development and evaluation of AI-based models rely significantly on access to comprehensive and meticulously annotated datasets. Unfortunately, publicly accessible datasets tailored for PSFHS are notably scarce. Bridging this critical gap, we introduce a PSFHS dataset comprising 1358 images, meticulously annotated at the pixel level. The annotation process adhered to standardized protocols and involved collaboration among medical experts. Remarkably, this dataset stands as the most expansive and comprehensive resource for PSFHS to date.

Do Birth Outcomes Predicted by Occipital Position Inform Definitions of Occiput Posterior and Occiput Transverse?

Fetal head position significantly influences birth outcomes, with higher rates of complications observed when the fetal head is in the Occiput Posterior (OP) position compared to Occiput Transverse (OT) or Occiput Anterior (OA) positions. There is no consensus in the current literature on the precise rotational point at which the fetal occiput shifts from posterior to transverse, reducing clarity in both scientific and clinical communication. Different studies employ varying definitions of these positions, which affects management decisions. This study aims to determine if a definable threshold exists between the directly posterior and directly transverse positions that correlates with different birth outcomes, thereby proposing a consistent and clinically useful definition for OP versus OT. We analyzed ultrasound data from 570 patients at full dilatation from five previous studies, correlating the angle of the fetal occiput (noted on a clock-face) with birth outcomes. Adverse outcomes were defined as cesarean delivery, instrumental vaginal delivery, significant postpartum hemorrhage (500 ml or more), obstetric anal sphincter injury, five-minute Apgar scores <7, arterial cord pH <7, base excess less than -12, or neonatal intensive care unit admission. The analysis was conducted using SAS version 9.4. The study found a continuous relationship between the fetal occipital angle and adverse birth outcomes without a distinct threshold separating OP from OT positions. No clear inflection point was demonstrated in pregnancy outcomes between OT and OP. The relationship between the angle of occiput position and pregnancy outcomes was continuous: the closer the fetal head was to directly OP, the higher the likelihood of adverse outcomes. Given the lack of a clear cut-off and to improve consistency in future research, we recommend dividing the occiput position into four quadrants of 90 degrees each. This classification could standardize reporting and potentially improve clinical decision-making regarding fetal position during labor.

Maternal rest improves growth in small-for-gestational-age fetuses (

Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question. This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus. A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Bonferroni Multiple Comparison Test. A P value of<.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included. A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001). Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

Decreased Sonographic Head Circumference Is Found in Buprenorphine-Exposed Fetuses [ID 2683396

INTRODUCTION: Neonates diagnosed with neonatal opioid withdrawal syndrome (NOWS) have decreased head circumference compared to non-exposed newborns. This is the first study to evaluate fetal head circumference over time in a group of fetuses with intrauterine buprenorphine exposure. METHODS: Fetal anatomic surveys are commonly performed at around 20 weeks of gestation. Patients treated with medication-assisted therapy (MAT) for opioid use disorder commonly receive estimated fetal weight scans at around 32 weeks of gestation due to the risk of intrauterine growth restriction. Retrospective review of ultrasound reports for three groups of patients were performed. Group 1 (75 patients) was low-dose MAT; group 2 (73 patients) was traditional higher-dose MAT. Group 3 (104 patients) was a control group. The IRB approval was 1220.9e-ETSU, entitled “Effect of Maternal Buprenorphine on Fetal Head Circumference.” RESULTS: At the time of the approximately 20-week scan, no statistical difference was found between the groups. At the approximately 32-week growth scan, however, a comparison of the two buprenorphine groups together versus control group showed a statistically significant difference (P=.018) in head circumference. Although the low-dose group had larger head circumferences than the higher-dose group in the 32-week scan, the difference was not significant. CONCLUSION: Previous studies have shown decreased head circumference in newborns in association with maternal MAT. This is the first study to provide ultrasound confirmation of decreased head circumference in fetuses exposed to buprenorphine. Effects are pronounced in the third trimester; the possibility exists that interventions during pregnancy might preserve fetal brain volume. Further research is needed.

Defining Architectural Changes in Mouse Pelvic Floor Muscles During Pregnancy to Withstand Physiological Distension Associated with Parturition

Pelvic floor disorders (PFDs), which are present in ~25% of women, profoundly impact quality of life. During childbirth, pelvic floor muscles (PFMs) endure substantial mechanical strain, which can lead to PFM dysfunction. As such, vaginal childbirth is a major risk factor for PFDs. Previous studies in rats demonstrate important structural adaptations in the PFMs that help to withstand the mechanical strain of childbirth, including muscle fiber lengthening by sarcomerogenesis. However, it is diffcult to establish a comprehensive understanding of the molecular mechanisms underlying PFM dysfunction during childbirth in rat models. Here, our objective was to determine if mouse PFMs undergo similar adaptations to rats during pregnancy and vaginal distension. We hypothesized that, akin to rats, PFMs in mice would undergo muscle fiber elongation through sarcomerogenesis during pregnancy. The PFMs (coccygeus [C], iliocaudalis [ICa], pubocaudalis [PCa]) and a non-pelvic floor muscle (tibialis anterior [TA]) were collected from late-pregnant (E16.5) and non-pregnant C57BL/6NJ (3 months old) mice. These animals were subjected or not subjected to physiological vaginal distension to mimic vaginal parturition (N = 4/group); in anesthetized mice, a 6F transurethral catheter was inserted into the vagina, and it was inflated with 0.3 mL (which best approximated fetal head circumference), and a 13 g weight was attached to the catheter creating circumferential and downward strains similar to parturition. Following this, the animals were euthanized, and the pelvis was fixed in situ for assessment of muscle architectural parameters; muscle fibers length was determined using digital calipers and sarcomere length was measured by light microscopy. Pregnancy induced a significant increase in normalized muscle fiber length in all PFMs compared to non-pregnant animals (Pregnant vs. not pregnant — C: 4.71±0.06 mm vs. 3.37±0.15 mm, p&lt;0.0001; ICa 8.74±0.14 mm vs. 7.50±0.27 mm, p=0.004; PCa 7.13±0.09 mm vs. 6.28±0.34 mm, p=0.04); TA muscle fiber length was unchanged (6.92±0.17 mm vs. 6.73 ± 0.19 mm, p=0.28). Sarcomere length was not affected by pregnancy in any muscle (C: 2.44±0.002 μm vs. 2.45 ± 0.003 μm, p=0.55; ICa: 2.26±0.003 μm vs. 2.26±0.004 μm, p=0.64; PCa: 2.16±0.01 μm vs. 2.16±0.003 μm, p=0.74; TA: 2.55±0.004 μm vs. 2.54±0.003 μm, p=0.28). Balloon-mediated vaginal distention resulted in significantly longer sarcomere lengths in non-pregnant compared to pregnant animals in all PFMs (C: 2.98±0.01 μm vs. 2.43±0.01 μm, p&lt;0.0001; ICa: 2.54±0.004 μm vs. 2.24±0.005 μm, p&lt;0.0001; PCa: 2.85±0.001 μm vs. 2.17±0.001 μm, p&lt;0.0001), indicating protection against sarcomere elongation in pelvic floor muscles of pregnant animals. This study shows that, similar to rats, pregnancy causes architectural changes in mouse pelvic floor muscles, which prevent excessive sarcomere stretching during physiologic vaginal distension that is comparable to fetal delivery. This work was funded by NIH grant #K12 HD000849 (Reproductive Scientist Development Program) to LAB and UC San Diego Senate Grant to LAB. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.