Transabdominal cerclage (TAC) is a recognised treatment for recurrent spontaneous late miscarriag... more Transabdominal cerclage (TAC) is a recognised treatment for recurrent spontaneous late miscarriage or preterm birth due to cervical weakness. This can be performed via an open procedure before and during pregnancy, or a laparoscopic technique preconception. Complications include cerclage failure and suture migration. We present a case highlighting these complications where laparoscopic removal of an open TAC and replacement led to two successful term deliveries. A 30-year-old African woman with a fibroid uterus, adenomyosis and a history of three spontaneous mid-trimester losses, had an open TAC at 13 weeks of gestation. Preterm premature rupture of the membranes (PPROM) occurred shortly after and at 18 weeks of gestation she underwent surgical evacuation of the uterus. Subsequent hysteroscopy confirmed migration of the cerclage through the cervical canal. We demonstrate the application of endoscopic gynaecological surgery to remove and replace the TAC with two successful term births by Caesarean section in the ensuing pregnancies.
Background: Epidural-related maternal fever (ERMF) has been reported in ~26% of labouring women. ... more Background: Epidural-related maternal fever (ERMF) has been reported in ~26% of labouring women. Explanatory mechanisms remain unclear. We hypothesized that ERMF is promoted by bupivacaine disrupting cytokine production/release from mononuclear leukocytes (MNF). We examined whether: (1) bupivacaine reduces caspase-1 activity and release of the anti-pyrogenic cytokine interleukin-1 receptor antagonist (IL-1ra); (2) bupivacaine is pro-inflammatory, through mitochondrial injury/interleukin-1β (IL-1β). Methods: In labouring women, blood samples were obtained before/after epidural analgesia was implemented. Maternal temperature was recorded hourly for the first 4h of epidural analgesia. Time-matched samples/temperatures were obtained from labouring women without epidural analgesia, pregnant, non-labouring and non-pregnant women. The primary clinical outcome was change in maternal temperature over four hours after onset of siting epidural catheter/enrolment. The secondary clinical outcome was development of ERMF (temperature ≥38 o C). The effect of bupivacaine/saline on apoptosis, caspase-1 activity, intracellular IL-1ra and plasma IL-1ra/IL-1β ratio was quantified in MNF from labouring women or THP-1 monocytes (using flow cytometry, respirometry and/or ELISA). Results: Maternal temperature increased by 0.06°C/h (95%CI:0.03-0.09); p=0.003; n=38) following labour epidural placement. ERMF only occurred in women receiving epidural analgesia (5/38; 13.2%). Bupivacaine did not alter MNF or THP-1 apoptosis, compared to saline-control, but reduced caspase-1 activity by 11% (95%CI:5-17); n=10) in MNF from women in established labour. Bupivacaine increased intracellular MNF IL-1ra by 25% (95%CI:10-41; p<0.001;n=10), compared to saline-control. Epidural analgesia reduced plasma IL-1ra/IL-1β ratio (mean reduction:14 (95%CI:7-30;n=30), compared to women without epidural analgesia.
Urinary tract infection is common in pregnancy. Urine is sampled from by mid-stream collection (M... more Urinary tract infection is common in pregnancy. Urine is sampled from by mid-stream collection (MSU). If epithelial cells are detected, contamination by vulvo-vagial skin and skin bacteria is assumed. Outside pregnancy, catheter specimen urine (CSU) is considered less susceptible to contamination. We compared MSU and CSU methods in term pregnancy to test these assumptions. Healthy pregnant women at term gestation (n = 32, median gestation 38 + 6 weeks, IQR 37 + 6-39 + 2) undergoing elective caesarean section provided a MSU and CSU for paired comparison that were each analysed for bacterial growth and bladder distress by fresh microscopy, sediment culture and immunofluorescent staining. Participants completed a detailed questionnaire on lower urinary tract symptoms. Epithelial cells found in urine were tested for urothelial origin by immunofluorescent staining of Uroplakin III (UP3), a urothelial cell surface glycoprotein. Urothelial cells with closely associated bacteria, or "c...
Ultrasound in Obstetrics & Gynecology, Sep 1, 2017
The coefficients of variation in mature fetuses were greater than 30% for placentas in-vivo, grea... more The coefficients of variation in mature fetuses were greater than 30% for placentas in-vivo, greater than 35 for placentas in-vitro, greater than 29% for liver tissue and greater than 33% for lung tissue. In mature fetuses strain index (SI) for fetal lung was greater than 0,9, for placentas in vivo greater than 1,0, for placentas in vitro, greater than 1,5, for liver tissue greater than 0,7. We found significant difference in SI in normal pregnancies comparing with pre-eclamptic pregnancies and diabetic pregnancies. We did not find significant difference between lung volumes in all investigated patients. Conclusions: The coefficient of variation values and strain stiffness for placentas in vivo and in vitro, and fetal lungs and liver increase during pregnancy in normal and pre-eclamptic patients with increasing gestational age and decrease in diabetic patients. Lung volumes increase during pregnancy in normal, pre-eclamptic and diabetic patients. Objectives: To determine the correlation between qualitative assessment of fetal bowel echogenicity and the quantitative measurements obtained by objective computerised Histogram method. Methods: This was a retrospective study conducted in 2016 at the University Medical Centre Groningen. We included all fetuses with EB evaluated at 19 +0 -21 +6 weeks of gestation. The subjective qualitative assessment of fetal bowel echogenicity was reported as mild, moderate and severe by fetal medicine experts. All pictures were stored digitally and retrospectively analysed using the ImageJ
To explore the concepts and strategies parents employ when considering maternal-fetal surgery (MF... more To explore the concepts and strategies parents employ when considering maternal-fetal surgery (MFS) as an option for the management of spina bifida (SB) in their fetus, and how this determines the acceptability of the intervention. A two-centre interview study enrolling parents whose fetuses with SB were eligible for MFS. To assess differences in acceptability, parents opting for MFS (n=24) were interviewed at three different moments in time: prior to the intervention, directly after the intervention and 3-6 months after birth. Parents opting for termination of pregnancy (n=5) were interviewed only once. Themes were identified and organised in line with the framework of acceptability. To parents opting for MFS, the intervention was perceived as an opportunity that needed to be taken. Feelings of parental responsibility drove them to do anything in their power to improve their future child's situation. Expectations seemed to be realistic yet were driven by hope for the best outcome. None expressed decisional regret at any stage, despite substantial impact and, at times, disappointing outcomes. For the small group of participants, who decided to opt for termination of pregnancy (TOP), MFS was not perceived as an intervention that substantially could improve the quality of their future child's life. Prospective parents opting for MFS were driven by their feelings of parental responsibility. They recognise the fetus as their future child and value information and This article is protected by copyright. All rights reserved. care focusing on optimising the child's future health. In the small group of parents opting for TOP, MFS was felt to offer insufficient certainty of substantial improvement in quality of life and the perceived severe impact of SB drove their decision to end the pregnancy.
Minimally invasive fetal interventions require accurate imaging from inside the uterine cavity. T... more Minimally invasive fetal interventions require accurate imaging from inside the uterine cavity. Twin-totwin transfusion syndrome (TTTS), a condition considered in this study, occurs from abnormal vascular anastomoses in the placenta that allow blood to flow unevenly between the fetuses. Currently, TTTS is treated fetoscopically by identifying the anastomosing vessels, and then performing laser photocoagulation. However, white light fetoscopy provides limited visibility of placental vasculature, which can lead to missed anastomoses or incomplete photocoagulation. Photoacoustic (PA) imaging is an alternative imaging method that provides contrast for hemoglobin, and in this study, two PA systems were used to visualize chorionic (fetal) superficial and subsurface vasculature in human placentas.
The placenta is essential for successful pregnancy outcome. Inadequate placenta development leads... more The placenta is essential for successful pregnancy outcome. Inadequate placenta development leads to poor placental perfusion and placental insufficiency, responsible for one third of antenatal stillbirths. Current imaging modalities provide poor clinical assessment of placental perfusion and pregnancy outcome. In this work we propose a technique to estimate the vascular properties of retro-placenta myometrial and placental perfusion. The fetal blood saturation is a relative unknown, thus we describe a method to simultaneously estimate the fetal blood volume in addition to the fetal blood T2 relaxation time from which we can estimate this parameter. This information may prove useful for predicting if and when a placenta will fail, and thus when a small baby must be delivered to have the best neurological outcome. We report differences in vascular compartments and saturation values observed between 5 normal pregnancies, and two complicated by placental insufficiency.
During fetoscopic laser photocoagulation, a treatment for twin-to-twin transfusion syndrome (TTTS... more During fetoscopic laser photocoagulation, a treatment for twin-to-twin transfusion syndrome (TTTS), the clinician first identifies abnormal placental vascular connections and laser ablates them to regulate blood flow in both fetuses. The procedure is challenging due to the mobility of the environment, poor visibility in amniotic fluid, occasional bleeding, and limitations in the fetoscopic field-of-view and image quality. Ideally, anastomotic placental vessels would be automatically identified, segmented and registered to create expanded vessel maps to guide laser ablation, however, such methods have yet to be clinically adopted. We propose a solution utilising the U-Net architecture for performing placental vessel segmentation in fetoscopic videos. The obtained vessel probability maps provide sufficient cues for mosaicking alignment by registering consecutive vessel maps using the direct intensity-based technique. Experiments on 6 different in vivo fetoscopic videos demonstrate that the vessel intensity-based registration outperformed image intensitybased registration approaches showing better robustness in qualitative and quantitative comparison. We additionally reduce drift accumulation to negligible even for sequences with up to 400 frames and we incorporate a scheme for quantifying drift error in the absence of the ground-truth. Our paper provides a benchmark for fetoscopy placental vessel segmentation and registration by contributing the first in vivo vessel segmentation and fetoscopic videos dataset.
During pregnancy, ultrasound examination in the second trimester can assess fetal size according ... more During pregnancy, ultrasound examination in the second trimester can assess fetal size according to standardized charts. To achieve a reproducible and accurate measurement, a sonographer needs to identify three standard 2D planes of the fetal anatomy (head, abdomen, femur) and manually mark the key anatomical landmarks on the image for accurate biometry and fetal weight estimation. This can be a timeconsuming operator-dependent task, especially for a trainee sonographer. Computer-assisted techniques can help in automating the fetal biometry computation process. In this paper, we present a unified automated framework for estimating all measurements needed for the fetal weight assessment. The proposed framework semantically segments the key fetal anatomies using state-of-the-art segmentation models, followed by region fitting and scale recovery for the biometry estimation. We present an ablation study of segmentation algorithms to show their robustness through 4-fold cross-validation on a dataset of 349 ultrasound standard plane images from 42 pregnancies. Moreover, we show that the network with the best segmentation performance tends to be more accurate for biometry estimation. Furthermore, we demonstrate that the error between clinically measured and predicted fetal biometry is lower than the permissible error during routine clinical measurements.
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Background: Spina bifida aperta (SBA) is a birth defect associated with severe anatomical changes... more Background: Spina bifida aperta (SBA) is a birth defect associated with severe anatomical changes in the developing fetal brain. Brain magnetic resonance imaging (MRI) atlases are popular tools for studying neuropathology in the brain anatomy, but previous fetal brain MRI atlases have focused on the normal fetal brain. We aimed to develop a spatio-temporal fetal brain MRI atlas for SBA. We developed a semi-automatic computational method to compute the first spatio-temporal fetal brain MRI atlas for SBA. We used 90 MRIs of fetuses with SBA with gestational ages ranging from 21 to 35 weeks. Isotropic and motion-free 3D reconstructed MRIs were obtained for all the examinations. We propose a protocol for the annotation of anatomical landmarks in brain 3D MRI of fetuses with SBA with the aim of making spatial alignment of abnormal fetal brain MRIs more robust. In addition, we propose a weighted generalized Procrustes method based on the anatomical landmarks for the initialization of the atlas. The proposed weighted generalized Procrustes can handle temporal regularization and missing annotations. After initialization, the atlas is refined iteratively using non-linear image registration based on the image intensity and the anatomical land-marks. A semi-automatic method is used to obtain a parcellation of our fetal brain atlas into eight tissue types: white matter, ventricular system, cerebellum, extra-axial cerebrospinal fluid, cortical gray matter, deep gray matter, brainstem, and corpus callosum.
Fetoscopy laser photocoagulation is a widely used procedure for the treatment of Twin-to-Twin Tra... more Fetoscopy laser photocoagulation is a widely used procedure for the treatment of Twin-to-Twin Transfusion Syndrome (TTTS), that occur in mono-chorionic multiple pregnancies due to placental vascular anastomoses. This procedure is particularly challenging due to limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to fluid turbidity, variability in light source, and unusual position of the placenta. This may lead to increased procedural time and incomplete ablation, resulting in persistent TTTS. Computer-assisted intervention may help overcome these challenges by expanding the fetoscopic field of view through video mosaicking and providing better visualization of the vessel network. However, the research and development in this domain remain limited due to unavailability of high-quality data to encode the intra-and inter-procedure variability. Through the Fetoscopic Placental Vessel Segmentation and Registration (FetReg) challenge, we present a large-scale multi-centre dataset for the development of generalized and robust semantic segmentation and video mosaicking algorithms for the fetal environment with a focus on creating drift-free mosaics from long duration fetoscopy videos. In this paper, we provide an overview of the FetReg dataset, challenge tasks, evaluation metrics and baseline methods for both segmentation and registration. Baseline methods results on the FetReg dataset shows that our dataset poses interesting challenges, offering large opportunity for the creation of novel methods and models through a community effort initiative guided by the FetReg challenge.
The performance of deep neural networks typically increases with the number of training images. H... more The performance of deep neural networks typically increases with the number of training images. However, not all images have the same importance towards improved performance and robustness. In fetal brain MRI, abnormalities exacerbate the variability of the developing brain anatomy compared to non-pathological cases. A small number of abnormal cases, as is typically available in clinical datasets used for training, are unlikely to fairly represent the rich variability of abnormal developing brains. This leads machine learning systems trained by maximizing the average performance to be biased toward non-pathological cases. This problem was recently referred to as hidden stratification. To be suited for clinical use, automatic segmentation methods need to reliably achieve high-quality segmentation outcomes also for pathological cases. In this paper, we show that the state-of-the-art deep learning pipeline nnU-Net has difficulties to generalize to unseen abnormal cases. To mitigate this problem, we propose to train a deep neural network to minimize a percentile of the distribution of per-volume loss over the dataset. We show that this can be achieved by using Distributionally Robust Optimization (DRO). DRO automatically reweights the training samples with lower performance, encouraging nnU-Net to perform more consistently on all cases. We validated our approach using a dataset of 368 fetal brain T2w MRIs, including 124 MRIs of open spina bifida cases and 51 MRIs of cases with other severe abnormalities of brain development.
Background Reducing the rate of stillbirth is an international priority. At least half of babies ... more Background Reducing the rate of stillbirth is an international priority. At least half of babies stillborn in high-income countries are small for gestational-age (SGA). The Growth Assessment Protocol (GAP), a complex antenatal intervention that aims to increase the rate of antenatal detection of SGA, was evaluated in the DESiGN type 2 hybrid effectiveness-implementation cluster randomised trial (n = 13 clusters). In this paper, we present the trial process evaluation. Methods A mixed-methods process evaluation was conducted. Clinical leads and frontline healthcare professionals were interviewed to inform understanding of context (implementing and standard care sites) and GAP implementation (implementing sites). Thematic analysis of interview text used the context and implementation of complex interventions framework to understand acceptability, feasibility, and the impact of context. A review of implementing cluster clinical guidelines, training and maternity records was conducted t...
Background Magnetic resonance imaging (MRI) provides excellent soft tissue visualisation which ma... more Background Magnetic resonance imaging (MRI) provides excellent soft tissue visualisation which may be useful in late pregnancy to predict labour outcome and maternal/neonatal birth trauma. Objective To study if MRI in late pregnancy can predict maternal and neonatal outcomes of labour and birth. Methods Systematic review of studies that performed MRI in late pregnancy or immediately postpartum. Studies were included if they imaged maternal pelvic or neonatal structures and assessed birth outcome. Meta-analysis was not performed due to the heterogeneity of studies. Results Eighteen studies were selected. Twelve studies explored the value of MRI pelvimetry measurement and its utility to predict cephalopelvic disproportion (CPD) and vaginal breech birth. Four explored cervical imaging in predicting time interval to birth. Two imaged women in active labour and assessed mouldability of the fetal skull. No marker of CPD had both high sensitivity and specificity for predicting labour outco...
Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfus... more Fetoscopy laser photocoagulation is a widely adopted procedure for treating Twin-to-Twin Transfusion Syndrome (TTTS). The procedure involves photocoagulation pathological anastomoses to restore a physiological blood exchange among twins. The procedure is particularly challenging, from the surgeon's side, due to the limited field of view, poor manoeuvrability of the fetoscope, poor visibility due to amniotic fluid turbidity, and variability in illumination. These challenges may lead to increased surgery time and incomplete ablation of pathological anastomoses, resulting in persistent TTTS. Computer-assisted intervention (CAI) can provide TTTS surgeons with decision support and context awareness by identifying key structures in the scene and expanding the fetoscopic field of view through video * Corresponding author.
This study demonstrates that, in women with a previous full-dilatation Cesarean section (CS), CS ... more This study demonstrates that, in women with a previous full-dilatation Cesarean section (CS), CS scar niche dimensions and scar position relative to the internal os of the uterine cervix can be assessed with a high level of reproducibility using B-mode and color Doppler transvaginal ultrasound during the second trimester of pregnancy. Full-dilatation CS increases the risk of spontaneous preterm birth in a subsequent pregnancy. There are currently no guidelines on how to measure CS scar position in pregnancy. The protocol described in this study should enable objective analysis of the effect of CS scar position and niche during pregnancy, and may be used in future studies to evaluate the associated risk of subsequent preterm birth.
The placenta plays a key contribution to successful pregnancy outcome. New MR imaging techniques ... more The placenta plays a key contribution to successful pregnancy outcome. New MR imaging techniques are able to reveal intricate details about placental structure and function and measure placental blood flow and feto-placental oxygenation. Placental diffusion-weighted MRI is however challenging due to maternal breathing motion and poor signal-to-noise ratio making motion correction important for subsequent quantitative analysis. In this work, we (i) introduce an iterative model-based registration technique which incorporates a placenta-specific model into the motion correction process and (ii) describe a new technique making use of a Bayesian shrinkage prior to obtain robust estimates of individual and population trends in parameters. Our results suggest that the proposed registration method improves alignment of placental data and that the Bayesian fitting technique allows the estimation of voxel-level placenta flow parameters and the population trend in each parameter with gestation...
Uploads
Papers by Anna David