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Nuffield Department of Women's & Reproductive Health sits within the Medical Sciences Division of the University of Oxford. The department encompasses multi-disciplinary research across four overarching themes; Cancer, Global Health, Maternal & Fetal Health and Reproductive Medicine & Genetics
Reference charts for first-trimester placental volume derived using OxNNet.
OBJECTIVE: To establish a comprehensive reference range for OxNNet-derived first-trimester placental volume (FTPV), based on values observed in healthy pregnancies. METHODS: Data were obtained from the First Trimester Placental Ultrasound Study, an observational cohort study in which three-dimensional placental ultrasound imaging was performed between 11 + 2 and 14 + 1 weeks' gestation, alongside otherwise routine care. A subgroup of singleton pregnancies resulting in term live birth, without neonatal unit admission or major chromosomal or structural abnormality, were included. Exclusion criteria were fetal growth restriction, maternal diabetes mellitus, hypertensive disorders of pregnancy or other maternal medical conditions (e.g. chronic hypertension, antiphospholipid syndrome, systemic lupus erythematosus). Placental images were processed using the OxNNet toolkit, a software solution based on a fully convolutional neural network, for automated placental segmentation and volume calculation. Quantile regression and the lambda-mu-sigma (LMS) method were applied to model the distribution of FTPV, using both crown-rump length (CRL) and gestational age as predictors. Model fit was assessed using the Akaike information criterion (AIC), and centile curves were constructed for visual inspection. RESULTS: The cohort comprised 2547 cases. The distribution of FTPV across gestational ages was positively skewed, with variation in the distribution at different gestational timepoints. In model comparisons, the LMS method yielded lower AIC values compared with quantile regression models. For predicting FTPV from CRL, the LMS model with the Sinh-Arcsinh distribution achieved the best performance, with the lowest AIC value. For gestational-age-based prediction, the LMS model with the Box-Cox Cole and Green original distribution achieved the lowest AIC value. The LMS models were selected to construct centile charts for FTPV based on both CRL and gestational age. Evaluation of the centile charts revealed strong agreement between predicted and observed centiles, with minimal deviations. Both models demonstrated excellent calibration, and the Z-scores derived using each of the models confirmed normal distribution. CONCLUSIONS: This study established reference ranges for FTPV based on both CRL and gestational age in healthy pregnancies. The LMS method provided the best model fit, demonstrating excellent calibration and minimal deviations between predicted and observed centiles. These findings should facilitate the exploration of FTPV as a potential biomarker for adverse pregnancy outcome and provide a foundation for future research into its clinical applications. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
First-trimester biomarkers of gestational diabetes mellitus: A scoping review.
Gestational diabetes mellitus (GDM) affects approximately 14% of pregnancies globally, with rising incidence depending on the diagnostic criteria used. In the UK, screening relies on risk factors at booking, followed by a diagnosis via an oral glucose tolerance test in the second trimester. This approach may lack sensitivity and has poor tolerability. Emerging evidence suggests that GDM pathophysiology begins in the first trimester, with biomarkers showing potential for early prediction. Identifying these could enable earlier risk stratification, improved diagnostic pathways, and better maternal-fetal outcomes. This scoping review maps the existing literature on first-trimester biomarkers of GDM to evaluate their clinical utility and integration into predictive models. A literature search was conducted using Medline, Embase, and PubMed to identify studies on first-trimester biomarkers of GDM. Inclusion criteria included (1) studies investigating biomarkers at <15 weeks' gestation; (2) studies that diagnosed GDM using an OGTT with recognized diagnostic guidelines or clearly stated glucose thresholds. A total of 133 studies were included, reporting a wide range of biomarkers (145 in total). PAPP-A was generally lower in GDM, with mixed findings for β-hCG and PlGF. Metabolic markers, including lipid profiles, fasting glucose, and HbA1c, were often elevated. Inflammatory markers, such as WCC, neutrophils, and CRP, were higher in those later diagnosed with GDM. First-trimester biomarkers highlight GDM's complex pathophysiology. PAPP-A shows predictive potential, while metabolic and inflammatory biomarkers suggest early systemic dysfunction. Emerging tools like 3D ultrasonography indicate placental structural changes. Larger studies are needed to validate these biomarkers and integrate them into predictive models to improve maternal-fetal outcomes.
The Effect of Weight Loss Before In Vitro Fertilization on Reproductive Outcomes in Women With Obesity : A Systematic Review and Meta-analysis.
BACKGROUND: It is unclear whether weight loss before in vitro fertilization (IVF) improves reproductive outcomes in women with obesity. PURPOSE: To assess whether weight loss interventions before IVF improve reproductive outcomes. DATA SOURCES: Five electronic databases through 27 May 2025. STUDY SELECTION: Randomized controlled trials (RCTs) in women with obesity who were offered a weight loss intervention before planned IVF. DATA EXTRACTION: Dual independent screening, data extraction, and assessment of risk of bias (RoB) and certainty of evidence. Primary outcomes were pregnancy and live birth rates. Where appropriate, studies were pooled using random-effects meta-analyses. DATA SYNTHESIS: Twelve RCTs (1921 randomly assigned participants) were included, 7 of which had high RoB. There was moderate certainty that pre-IVF weight loss interventions were associated with an increase in total pregnancy rates (risk ratio [RR], 1.21 [95% CI, 1.02 to 1.44]; 11 studies) and pregnancies resulting from unassisted conception (RR, 1.47 [CI, 1.26 to 1.73]; 10 studies), whereas the effect on pregnancies resulting solely from IVF was uncertain. Weight loss interventions were not associated with pregnancy loss rates (RR, 1.05 [CI, 0.98 to 1.13]; 8 studies; moderate certainty), but their effect on live birth rates was unclear (RR, 1.15 [CI, 0.95 to 1.40]; 9 studies; very low certainty). LIMITATIONS: Studies were small, had high RoB, and often did not report important outcomes, such as live births. Substantial clinical and methodological heterogeneity was unexplained by exploratory analyses. CONCLUSION: Weight loss interventions before IVF appear to increase the chances of pregnancy, especially unassisted conceptions. However, studies were small, and heterogeneity made it difficult to determine the benefit of any particular intervention. PRIMARY FUNDING SOURCE: National Institute for Health and Care Research Applied Research Collaboration Oxford and Thames Valley. (PROSPERO: CRD42023441457).
First trimester maternal infections and offspring congenital heart defects: a meta-analysis.
BACKGROUND AND AIMS: Maternal infections have been proposed to play a role in the development of congenital heart defects (CHD). This study aims to synthesize contemporary evidence on the association between first-trimester maternal infection and risk of offspring CHD. METHODS: This systematic review and meta-analysis (PROSPERO number: CRD42024523638) used Embase, PubMed, Web of Science, Scopus, and the Cochrane Library to identify studies investigating first-trimester maternal infection and offspring CHD, published up until 30 September 2024. Human studies with a minimum of 50 cases were eligible. Inverse variance weighted random-effects models were conducted to pool estimates and stratify associations by infection type and heart defect type. RESULTS: A total of 30 studies (24 case-control, 3 cohort, and 3 cross-sectional studies) with 1 732 295 pregnancies were identified. Studies assessed maternal infectious status through self-reported questionnaires (n = 20, 66.7%), laboratory testing (n = 7, 23.3%) or medical records (n = 3, 10.0%). Overall, any first-trimester maternal infection was associated with higher risk of CHD in offspring, with a pooled odds ratio (OR) and 95% confidence interval (CI) of 1.63 (1.41, 1.88). Among specific types of infection, rubella virus, coxsackievirus, respiratory infections, and influenza presented higher risks of offspring CHD, with ORs (95% CI) of 2.78 (2.08, 3.72), 1.57 (1.12, 2.19), 1.57 (1.25, 1.96), and 1.50 (1.20, 1.87), respectively. Studies that reported associations by individual subtype of CHD relied on a comparatively modest number of cases. Pooled ORs for exposure to any first-trimester infection were 1.59 (1.16, 2.20) for ventricular septal defects, 1.55 (1.21, 1.99) for atrioventricular septal defects, and not statistically significant for other subtypes. CONCLUSIONS: First-trimester maternal infections are associated with increased risk of offspring CHD and appear to extend beyond infections commonly tested for during routine pregnancy screening. Larger-scale studies are warranted to confirm these findings using laboratory antibody testing and explore underlying mechanisms.
Subclinical Postpartum Renal Structure After Hypertensive Pregnancy Disorders.
BACKGROUND: Hypertensive pregnancies are associated with increased risks of renal failure in pregnancy and later life. However, traditional markers of renal function normalize postpartum, making identification of those at future disease risk difficult. We studied whether the type and severity of hypertensive pregnancy associated with postpartum renal structure. METHODS: One hundred twenty-five women from interventional trials (61 preeclamptic, 33 gestational hypertension, and 31 normotensive pregnancy), aged ≥18 years, were imaged using magnetic resonance imaging 6 to 12 months postpartum. Anthropometric, demographic, blood pressure, and blood sample data were collected during pregnancy and postpartum. Kidney volume indexed to body surface area and corticomedullary differentiation were compared between groups using a 1-way ANCOVA, whereas associations with other outcomes were assessed using correlation tests. RESULTS: Postpartum total kidney volume indexed to body surface area was smaller in women who had preeclampsia compared with those who had gestational hypertension or a normotensive pregnancy (P=0.049). Total kidney volume postpartum correlated with estimated glomerular filtration rate at delivery (P<0.001). However, smaller volumes were not explained by reduced corticomedullary differentiation, which only differed in women with gestational hypertension compared with preeclamptic (P=0.02) and normotensive women (P=0.007). There were no associations between renal measures and blood pressure during or after pregnancy. CONCLUSIONS: At 6 to 12 months postpartum, preeclamptic women have smaller kidney volumes than women with gestational hypertension or normotensive pregnancies. These smaller volumes relate to lower renal function at delivery but not corticomedullary differentiation, which only differed in women with gestational hypertension. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT04273854 and NCT05434195.
The range and reach of qualitative research in neurosurgery: A scoping review.
Following calls for more qualitative research in neurosurgery, this scoping review aimed to describe the range and reach of qualitative studies relevant to the field of neurosurgery and the patients and families affected by neurosurgical conditions. A systematic search was conducted in September 2024 across six databases: Medline via Ebsco; Embase via OVID; PsycINFO via Ebsco; Scopus; Web of Science Core Collection; and Global Health via Ebsco. Eligibility criteria were based on Population, Concept, and Context. The search identified 18,809 hits for screening with 812 included in the final analysis. Seven themes were identified from a content analysis of study aims: 1 Perspectives of living with a neurosurgical condition; 2 Family perspectives; 3 Perceptions of neurosurgery; 4 Perceptions of general healthcare care; 5 Decision making; 6 Advancing neurosurgery; and, 7 Understanding neurosurgical conditions. Traumatology was identified as the most researched sub-specialty (43.2%) yet few studies were led explicitly by a neurosurgeon (1.6%) or those with a neurosurgical affiliation (10.5%). Lead authors were predominantly from high income countries (93.7%), as were most multi-author teams (86.6%). There was a trend towards increasing publication over time; however, only 8.4% of papers were published in neurosurgical specific journals. The data set had an average Field Weighted Citation Impact of 0.96 and Field Weighted Views Impact of 1.11, 18.9% were cited in policy documents in 15 countries. This scoping review provides a comprehensive picture of the current qualitative research base in neurosurgery and suggests ways to improve the conduct and reporting of such studies in the future. Addressing these challenges is crucial if qualitative research is to advance the neurosurgical evidence base in a rigorous way.
Women in science: bridging gaps in basic sciences.
The Supporting Women in Science (SWIS) program aims to strengthen female representation in research in developing countries. This article highlights the program participation, mentorship challenges, and systemic barriers. Findings inform inclusive, discipline-specific strategies designed to support women's research capacity, academic leadership, and advancement in the global scientific community.
Systematic review and meta-analysis of the importance of pre-pregnancy maternal health on the risk of hypertensive disorders of pregnancy.
Stratifying women using their medical history pre-pregnancy may allow early identification of women at high-risk of Hypertensive disorders of pregnancy (HDP), a common and high-burden obstetrical complication. This would allow the establishment of early preventative approaches, however, most research into pregestational conditions comes from data taken during pregnancy. To address this gap, we conducted a systematic review with meta-analysis, adhering to PRISMA and MOOSE guidelines. Our review comprehensively examined the impact of a broad range of medical disorders exclusively diagnosed pre-pregnancy on the development of HDP, including preeclampsia, gestational hypertension, superimposed preeclampsia, eclampsia and HELLP. We searched Medline (OvidSP) and Embase (OvidSP) databases from inception to 8th May 2021 and calculated relative risks ratios, adjusted for study quality, or percentage incidences. 406/8724 studies were included for qualitative research, 177 of which classified for quantitative assessment. HDP risk increased with pregestational renal conditions (7.76, CI: 5.62-10.71), hypertension (3.68, CI: 1.51-8.97), diabetes (3.57, CI: 2.71-4.70), and high body mass index (2.65, CI: 2.33-3.03); as well as with pregestational polycystic ovarian syndrome (1.90, CI: 1.46-2.48), rheumatoid arthritis (1.54, CI: 1.42-1.67), migraines (1.53, CI: 1.32-1.78), and anxiety/depression (1.52, CI: 1.16-2.00). Pregestational antiphospholipid syndrome, systemic lupus erythematosus, and Takayasu arteritis also increased the incidence of gestational hypertension (8 %, 7 %, 17 %) and preeclampsia (37 %, 17 %, 23 %). Overall, this review shows pre-pregnancy maternal health can help stratify HDP risk, and highlights the importance of often-overlooked risk factors in current national guidelines and assessment tools. Crucially, we provide an evidence-based graphical abstract/list of the identified pregestational risk factors as reference for medical practitioners providing pre-pregnancy counselling.
Oversized nanodiscs for combined structural and functional investigation of multicomponent membrane protein systems
Membrane proteins are fundamental to many crucial cellular processes but removing them from their native environment for structural and functional studies creates experimental challenges. Numerous strategies have been developed to replicate native-like membrane environments in vitro for membrane protein research, however, most studies have focused on systems for either structural or functional characterisation, not both together. Here, we apply an in-vivo split intein strategy to produce stable circularised nanodiscs for combined structural and functional analysis of respiratory complex I, using its highly hydrophobic native ubiquinone-10 substrate and an auxiliary ubiquinol oxidase from Trypanosoma brucei brucei. We successfully reconstituted Paracoccus denitrificans complex I into circularised nanodiscs, determined its cryo-EM structure at 3.1 Å resolution and conducted biophysical and biochemical analyses to demonstrate how the ‘oversized’ nanodiscs have space to accommodate both enzymes and substrates to sustain steady-state catalysis. Our work establishes a proof-of-principle for using oversized nanodiscs as an integrated platform for structural and functional interrogation of complex membrane proteins in near-native membrane environments.
Digital Technologies for Improving Pregnancy Care
Reducing maternal mortality remains a global challenge. Weaknesses in health systems are an important contributor to deaths around the world. Digital technologies could accelerate progress and support maternity services worldwide. Many digital innovations have been developed and implemented in maternity services. These target: the end users themselves (i.e., the pregnant woman and her family) to improve health knowledge and health-seeking behaviors; the primary and secondary care health workers in the community to support decision-making, scheduling, and referrals; and the health system and health management supporting the tracking of births and deaths. This chapter outlines the case for digital health innovations to support pregnancy and maternity services through a series of case studies, considering the potential advantages and challenges of scale-up. While the examples presented are not specific to Muslim populations, they have potential relevance for the challenges faced in Muslim countries worldwide.
Prenatal detection of congenital heart defects using the deep learning-based image and video analysis: protocol for Clinical Artificial Intelligence in Fetal Echocardiography (CAIFE), an international multicentre multidisciplinary study.
INTRODUCTION: Congenital heart defect (CHD) is a significant, rapidly emerging global problem in child health and a leading cause of neonatal and childhood death. Prenatal detection of CHDs with the help of ultrasound allows better perinatal management of such pregnancies, leading to reduced neonatal mortality, morbidity and developmental complications. However, there is a wide variation in reported fetal heart problem detection rates from 34% to 85%, with some low- and middle-income countries detecting as low as 9.3% of cases before birth. Research has shown that deep learning-based or more general artificial intelligence (AI) models can support the detection of fetal CHDs more rapidly than humans performing ultrasound scan. Progress in this AI-based research depends on the availability of large, well-curated and diverse data of ultrasound images and videos of normal and abnormal fetal hearts. Currently, CHD detection based on AI models is not accurate enough for practical clinical use, in part due to the lack of ultrasound data available for machine learning as CHDs are rare and heterogeneous, the retrospective nature of published studies, the lack of multicentre and multidisciplinary collaboration, and utilisation of mostly standard planes still images of the fetal heart for AI models. Our aim is to develop AI models that could support clinicians in detecting fetal CHDs in real time, particularly in nonspecialist or low-resource settings where fetal echocardiography expertise is not readily available. METHODS AND ANALYSIS: We have designed the Clinical Artificial Intelligence Fetal Echocardiography (CAIFE) study as an international multicentre multidisciplinary collaboration led by a clinical and an engineering team at the University of Oxford. This study involves five multicountry hospital sites for data collection (Oxford, UK (n=1), London, UK (n=3) and Southport, Australia (n=1)). We plan to curate 14 000 retrospective ultrasound scans of fetuses with normal hearts (n=13 000) and fetuses with CHDs (n=1000), as well as 2400 prospective ultrasound cardiac scans, including the proposed research-specific CAIFE 10 s video sweeps, from fetuses with normal hearts (n=2000) and fetuses diagnosed with major CHDs (n=400). This gives a total of 16 400 retrospective and prospective ultrasound scans from the participating hospital sites. We will build, train and validate computational models capable of differentiating between normal fetal hearts and those diagnosed with CHDs and recognise specific types of CHDs. Data will be analysed using statistical metrics, namely, sensitivity, specificity and accuracy, which include calculating positive and negative predictive values for each outcome, compared with manual assessment. ETHICS AND DISSEMINATION: We will disseminate the findings through regional, national and international conferences and through peer-reviewed journals. The study was approved by the Health Research Authority, Care Research Wales and the Research Ethics Committee (Ref: 23/EM/0023; IRAS Project ID: 317510) on 8 March 2023. All collaborating hospitals have obtained the local trust research and development approvals.
Diagnostic ultrasound to inform the surgical approach to cesarean delivery in patients at high risk for placenta accreta spectrum disorders
Background Uterine sparing surgery has become an option for patients with placenta accreta spectrum disorders. The decision to perform a cesarean hysterectomy versus uterine sparing surgery is made intraoperatively. This study was undertaken to assess the value of ultrasound markers in predicting hysterectomy. Objective To describe ultrasound markers associated with the need for cesarean hysterectomy in patients at risk of placenta accreta spectrum. Study design This was an analysis of a prospectively collected data of high risk placenta accreta spectrum patients between September 2023 and August 2024. Ultrasound examination was performed by an expert focusing on the diagnosis of placenta accreta spectrum. All patients were counselled regarding the management options available at our center, namely uterine-sparing surgery and hysterectomy. All patients opted for a uterine sparing surgery if safe and technically feasible. The final choice of surgical management approach was solely based on the intraoperative topography which describes the size and location of the abnormally adhered placenta. The primary outcome was the need for hysterectomy despite a preoperative plan for uterine-sparing surgery. Results A total of 123 participants were enrolled: 93 placenta accreta spectrum cases and 30 non-placenta accreta scar dehiscence cases. Uterine sparing surgery was successful in 74 out of 93(79.6%) placenta accreta spectrum cases and 100% non-placenta accreta scar dehiscence cases. Least Absolute Shrinkage and Selection Operator penalised regression revealed intracervical hypervascularity >50%, distorted urinary bladder wall, and parametrial hypervascularity as the most influential predictors for hysterectomy. This best-fitted model achieved accuracy of 94% (95% CI: 81.3% – 99.3%) after model cross-validation. The combination of intracervical hypervascularity >50% and distorted bladder wall had the highest predictive probability for hysterectomy, with a value of 0.87 (95% CI: 0.81 – 0.93), sensitivity of 96.0% (95% CI 89.0 – 99.0%) and specificity of 92.0%(95% CI 62.0 – 100.0). Conclusion Comprehensive preoperative ultrasound can reasonably predict the appropriate surgical approach to placenta accreta spectrum. This can be achieved by assessing intracervical hypervascularity and a distorted urinary bladder wall using a combination of transabdominal, transvaginal, and color Doppler ultrasound techniques, as these signs have a strong correlation with the need for hysterectomy in a cohort where the intention to treat was uterine sparing surgery.
"Is she pregnant with Jesus?" exploring sociocultural obstacles to following medical advice in the context of stillbirth prevention in Nigeria.
BACKGROUND: Each year 182,000 babies are stillborn in Nigeria, representing nearly 10% of the annual global stillbirth burden. Imo state in south-eastern Nigeria has one of the highest levels of maternal health service access in Nigeria, yet this has not translated into good pregnancy outcomes. Many stillbirth prevention initiatives in Nigeria focus on maternal health education but empirical evidence suggests that sociocultural factors impact healthcare choices and outcomes. This study aims to explore women's and health workers' perspectives of the sociocultural barriers to following medical advice during pregnancy and childbirth, and specifically how these barriers may contribute to an increased risk of stillbirth. This study is part of a broader community-based stillbirth prevention mixed-methods research in Imo State, Nigeria. METHODS: A qualitative descriptive study was conducted using in-depth interviews and focus group discussions. 38 participants were purposively recruited; 20 women and 18 health workers. Audio recordings were transcribed, translated and analysed using inductive thematic analysis. RESULTS: Four themes were identified: (1) trust, where scepticism about health worker motives or competence and trust in community informal networks were highlighted (2) power dynamics within families, with husbands and older female relatives influencing health decisions; (3) personal and community beliefs that undermine confidence in medical interventions, including a pervasive stigma associated with caesarean section; and (4) grassroots proposals for solutions, emphasising the importance of a whole-community approach to maternal health education, mobilising peer voices, engaging traditional leaders and training of traditional birth attendants. CONCLUSION: This study provides insights into the sociocultural barriers to following medical advice during pregnancy in Nigeria, which include a lack of trust in health professionals, power dynamics within a woman's family, and entrenched cultural and religious beliefs that oppose medical intervention. Women's decisions about pregnancy and childbirth are heavily influenced by family and cultural norms. Culturally sensitive, community-wide interventions which aim to rebuild trust in the health system, involve women as decision-makers in antenatal care, and engage religious and traditional leaders would be beneficial for improving outcomes.
Rates and risk factors for antepartum and intrapartum stillbirths in 20 secondary hospitals in Imo state, Nigeria: A hospital-based case control study.
Despite Nigeria's stillbirth rate reducing from 28.6 to 22.5 per 1,000 births from 2000-2021, progress trails comparable indicators and regional variations persist. We assessed stillbirth incidences and associated risk factors in 20 secondary hospitals in Imo state, to generate essential local evidence to inform policymaking to reduce mortality. The total numbers of births and their outcomes were determined through hospital maternity registers. An unmatched case-control study was conducted. We collected retrospective data about 157 antepartum and 193 intrapartum stillbirths, and from 381 livebirths (controls). Potential risk factors were categorised into sociodemographic, obstetric and maternity care and biological determinants using a theoretical framework. Independent multivariable logistic regression models were used to investigate the association of risk factors with each stillbirth type. The overall stillbirth rate was 38 per 1,000 total births. The rate of antepartum and intrapartum stillbirths were 16 and 19 per 1,000 respectively. The risk factors independently associated with antepartum stillbirths were nulliparity (adjusted odds ratio (aOR) 1.87, 95%CI 1.04-3.36); preterm birth (aOR 14.29, 95%CI 6.31-32.38); being referred from another facility (aOR 3.75, 95%CI 1.96-7.17); unbooked pregnancy (aOR 2.58, 95%CI 1.37-4.85); and obstetric complications (aOR 4.04, 95%CI 2.35-6.94). For intrapartum stillbirths, associated factors were preterm birth (aOR 11.28, 95%CI 4.66-27.24); referral (aOR 2.50, 95%CI 1.19-5.24); not using a partogram (aOR 2.92, 95%CI 1.23-6.95) and obstetric complications (aOR 10.71, 95%CI 5.92-19.37). The findings highlight specific risk factors associated with antepartum and intrapartum stillbirths, shedding light on potential areas for targeted interventions.
Socio-spatial equity analysis of relative wealth index and emergency obstetric care accessibility in urban Nigeria.
BACKGROUND: Better geographical accessibility to comprehensive emergency obstetric care (CEmOC) facilities can significantly improve pregnancy outcomes. However, with other factors, such as affordability critical for care access, it is important to explore accessibility across groups. We assessed CEmOC geographical accessibility by wealth status in the 15 most-populated Nigerian cities. METHODS: We mapped city boundaries, verified and geocoded functional CEmOC facilities, and assembled population distribution for women of childbearing age and Meta's Relative Wealth Index (RWI). We used the Google Maps Platform's internal Directions Application Programming Interface to obtain driving times to public and private facilities. City-level median travel time (MTT) and number of CEmOC facilities reachable within 60 min were summarised for peak and non-peak hours per wealth quintile. The correlation between RWI and MTT to the nearest public CEmOC was calculated. RESULTS: We show that MTT to the nearest public CEmOC facility is lowest in the wealthiest 20% in all cities, with the largest difference in MTT between the wealthiest 20% and least wealthy 20% seen in Onitsha (26 vs 81 min) and the smallest in Warri (20 vs 30 min). Similarly, the average number of public CEmOC facilities reachable within 60 min varies (11 among the wealthiest 20% and six among the least wealthy in Kano). In five cities, zero facilities are reachable under 60 min for the least wealthy 20%. Those who live in the suburbs particularly have poor accessibility to CEmOC facilities. CONCLUSIONS: Our findings show that the least wealthy mostly have poor accessibility to care. Interventions addressing CEmOC geographical accessibility targeting poor people are needed to address inequities in urban settings.