Obstetric Anesthesiology Research
Advancing Obstetric and Perinatal Anesthetic Care
Our Research Faculty
Our faculty are internationally recognized experts in obstetric anesthesiology.
We aim to advance the health and well-being of mothers by:
- Ensuring each woman obtains high-quality pain relief during and after her delivery.
- Identifying approaches for preventing and treating postpartum hemorrhage.
- Expanding knowledge related to women’s recovery after delivery.
Featured Researchers
How our research has changed practice
Research from our group has been instrumental in advancing maternal and peripartum care. Through our research, we have developed new protocols and approaches for preventing and managing postpartum hemorrhage, enhanced methods to manage mothers’ pain during labor and after cesarean delivery, improved knowledge of how drugs behave in the peripartum setting, and designed instruments to measure recovery after childbirth.
Research Recognition
Our faculty have gained recognition for their outstanding contributions to innovation and knowledge in peripartum care and obstetric anesthesiology. Our work has received funding support from the National Institute for Health, Stanford Maternal & Child Health Research Institute and industry partners. Our research has been recognized with the receipt of numerous scientific awards from several international medical societies.
At the Society of Obstetric Anesthesiology and Perinatology annual scientific meetings, the most prestigious obstetric anesthesia meeting in the world, we have won the Best Scientific Paper award on 3 occasions, and been a finalist for this award on 7 occasions. Our trainee-mentored research has been consistently recognized with an unprecedented 13 Resident/Fellow Research Presentation awards in the past 18 years. We have also received scientific meeting research awards from the American Society of Anesthesiology, Obstetric Anaesthetists’ Association of Great Britain, and the Canadian Anesthesiologists' Society.
Our work has been published in high-impact scientific journals on numerous occasions (see all publications). We have produced and contributed towards several national guidelines and consensus statements produced by the Society of Obstetric Anesthesiology and Perinatology, the American Heart Association and the World Health Organization.
Our obstetric anesthesia facility was the first in the nation to be designated as a Society for Obstetric Anesthesia and Perinatology Center of Excellence, and Brendan Carvalho was appointed as President of the Society for Obstetric Anesthesia and Perinatology between 2017 and 2018.
Recent Publications

Publications
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Snapshot of Obstetric National Audit and Research Project (SONAR1): aprotocol for an international observational cohort study.
BMJ open
2025; 15 (6): e103525
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Abstract
Caesarean birth (CB) under neuraxial anaesthesia (NA) is the most performed inpatient operation in the UK. The incidence of intraoperative pain during caesarean delivery performed under neuraxial anaesthesia is unclear, with limited data that used patient-reported measures to investigate intraoperative pain. The short- and medium-term impacts on patients of this adverse event are unknown.We will undertake a multicentre, prospective observational cohort study to evaluate the incidence and impact of pain experienced by patients during CB performed under neuraxial anaesthesia. Routine audit data will be collected for all patients undergoing caesarean delivery for any indication during a 1 week window at participating hospitals within the UK and Queensland, Australia. The dataset will include patient, anaesthetic, obstetric and neonatal risk factors for intraoperative pain. Local investigators will then seek informed consent from patients either before or within 24 hours of delivery to record patient experience and patient-reported outcomes at 24 hours and 6 weeks postdelivery. Local investigators at participating hospitals will also complete a survey evaluating compliance with evidence-based structural standards at their sites. The patient characteristics, structures, processes and outcomes will be described. Inferential techniques will be used to evaluate the relationship between risk factors and postoperative outcomes.This study received ethical approval from the Leicester Health Research Authority and Care Research Wales, REC reference 24/EM/0084) on 24 May 24. The study received ethical approval from the Human Research Ethics Committee of Metro North Health in Australia on 25 March 2024 (REC Ref HREC/2024/MNHA/103767). The results of the study will be reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology statement. The results will be disseminated via conference presentations, peer-reviewed academic journals and reports prepared for patients, the public and policy makers.ISRCTN15269213.
View details for DOI 10.1136/bmjopen-2025-103525
View details for PubMedID 40555454
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Improving epidemiology synthesis of postpartum complications: methodological considerations.
American journal of obstetrics and gynecology
2025
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View details for DOI 10.1016/j.ajog.2025.06.031
View details for PubMedID 40545214
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Peri-operative use of high-flow nasal oxygen in obstetric patients: a systematic review.
Anaesthesia
2025
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Abstract
INTRODUCTION: High-flow nasal oxygen devices have gained interest in pre-oxygenation and peri-operative oxygenation strategies. However, their role in obstetric anaesthesia remains poorly defined. This systematic review aimed to evaluate the use of high-flow nasal oxygen in obstetric patients during the peri-operative period, focusing on maternal oxygenation and clinical outcomes.METHODS: We included studies published in any language, conducted in all countries. Search terms included terminology concerning obstetric anaesthesia related to the use of high-flow nasal oxygen in the peri-operative period. Included papers were assessed for risk of bias. Studies were included for detailed review if they evaluated the use of high-flow nasal oxygen as a pre-oxygenation strategy in obstetric patients and reported maternal or neonatal outcomes.RESULTS: A total of 649 abstracts were screened with 11 articles included. There was variation in pre-oxygenation strategies and primary outcomes. Available evidence suggests that high-flow nasal oxygen was not superior to facemask pre-oxygenation in achieving target end-tidal oxygen concentrations. High-flow nasal oxygen may increase the partial pressure of oxygen in arterial blood, but the evidence of increased apnoea time was inconsistent. There were no reported adverse maternal effects or differences in neonatal Apgar scores, umbilical cord gases or fetal heart rate assessments.DISCUSSION: The advantages of peri-operative high-flow nasal oxygen over conventional oxygenation methods for obstetric patients remain uncertain. Current evidence does not show a clear benefit of high-flow nasal oxygen in achieving pre-oxygenation targets or prolonging time to desaturation in low-risk patients, whilst the benefits in high-risk patients remain uncertain and warrant further investigation.
View details for DOI 10.1111/anae.16665
View details for PubMedID 40528730
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Delphi study to develop a core outcome set for inpatient pain assessment after cesarean delivery.
Anaesthesia, critical care & pain medicine
2025: 101556
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Abstract
Studies of cesarean delivery pain report different outcomes, restricting data pooling. The study aimed to develop a core outcome set for inpatient postoperative pain assessment after cesarean delivery to use for research and clinical practice, using the Delphi consensus methodology.A scoping review identified 37 initial outcomes, with 2 additional outcomes developed from a focus group. These were rated in a two-round Delphi survey completed by the focus group consisting of authors of studies from the scoping review (n = 9), supplemented with other experts (n = 5) and patients with recent lived experience (n = 7). Scores were on a 1-5 Likert scale, 1-2 being 'critical for inclusion'; 3 being 'important but not critical', and 4-5 of 'limited importance/invalid'. Outcomes were included if recommended by ≥70% of stakeholders after voting. A third-round virtual meeting determined domains, and several further rounds of online surveys, the specific measures.Round one included 14 experts and 7 patients. Round two included 12 experts and 4 patients (76% response). The virtual meeting was attended by 11 experts and 3 patients (67%), and the 4 online surveys were completed by 67%, 52%, 67%, and 76% of the focus group. The final domains included pain intensity: at rest, movement-evoked, and pain relief; pain interference; total consumption of opioids; and maternal adverse effects. 12 measures for domains were agreed upon.Getting out of a hospital bed was selected as the most relevant functional activity for movement-evoked pain after cesarean delivery. This core outcome set may be applied to future research and clinical practice.
View details for DOI 10.1016/j.accpm.2025.101556
View details for PubMedID 40441486
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Frequency and timing of complications within the first postpartum year in the United States and Canada: A systematic review and meta-analysis.
American journal of obstetrics and gynecology
2025
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Abstract
Understanding the rates and timing of postpartum complications can facilitate timely screening and management to reduce preventable morbidity and mortality. The aim of this study was to summarize the frequency (prevalence or incidence) and timing of complications from hospital delivery to one year postpartum in the United States and Canada.PubMed MEDLINE, Web of Science, EBSCO CINAHL, and the Cochrane CENTRAL and Database of Systematic Reviews were reviewed from January 1, 2010, until December 31, 2024.Inclusion criteria were studies written in English reporting the frequency and timing of medical, procedural/surgical, and psychosocial complications in adults in the United States and Canada, from hospital delivery to 1 year postpartum. Studies with less than 100 patients, not reporting the timing of evaluation, or only included patients with a specific medical condition (e.g. preeclampsia) were excluded.Data screening, extraction, and appraisal were performed by two reviewers. The appraisal tool was the Joanna Briggs Institute instrument for studies reporting prevalence data. Meta-analysis using random effects modelling was performed if a complication was reported in two or more studies.Out of 4874 retrieved articles, 117 were included (93 original investigations, 24 reviews). The total sample size from original investigation studies was 246,521,464 patients (median (interquartile range) 6,030 (513 to 327,066) per study). In total, 41 complications and mortality data were extracted, with significant heterogeneity amongst definitions and time points of measurements. The one-year postpartum frequency estimates from meta-analysis (per 10,000, with 95% confidence interval) were anxiety 1,380 (845 - 2,174), depression 1008 (749 - 1,343), hypertension 890 (345 - 2,109), obsessive compulsive disorder 996 (134 - 4,089), hemorrhage 591 (454 - 763), post-traumatic stress disorder 464 (188 - 1,100), surgical infection 581 (12 - 7,678), postpartum severe maternal morbidity 100 (38 - 260), venous thromboembolism 17 (13 - 24), sepsis 11 (8 - 15), cardiomyopathy 1.9 (0.5 - 6.8), severe sepsis 1.2 (0.2 - 9.0), cardiac arrest 0.9 (0.2 to 1.0), acute myocardial infarction 0.25 (0.06 - 1.03), and mortality 1.2 (0.3 - 5.6).We report frequencies and timings for 41 complications and mortality from delivery to one year postpartum. Of the nine complications that underwent meta-analysis, anxiety, depression, hypertension and hemorrhage were reported most frequently. These results can inform evidence-based resource allocation and guide optimal postpartum monitoring and care pathway development.
View details for DOI 10.1016/j.ajog.2025.04.060
View details for PubMedID 40334769