Obstetric Anesthesiology Research

Advancing Obstetric and Perinatal Anesthetic Care

Research Mission Statement

To advance knowledge in the field of obstetric anesthesiology and peripartum care through clinical, epidemiological, and outcomes-based research.

Research Vision Statement

To optimize and personalize maternal care provided by obstetric anesthesiologists.


Our Research Faculty

Our faculty are internationally recognized experts in obstetric anesthesiology. 

We aim to advance the health and well-being of mothers by:

  1. Ensuring each woman obtains high-quality pain relief during and after her delivery.
  2. Identifying approaches for preventing and treating postpartum hemorrhage.
  3. Expanding knowledge related to women’s recovery after delivery.

Featured Researchers

Brendan Carvalho, MD
CAP Profile

Pamela Flood, MD
CAP Profile

Alex Butwick, MD
CAP Profile

Pervez Sultan, MD
CAP Profile

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

Professor of Anesthesiology, Perioperative and Pain Medicine (Adult MSD) at the Stanford University Medical Center


  • Integrated trajectories of the maternal metabolome, proteome, and immunome predict labor onset. Science translational medicine Stelzer, I. A., Ghaemi, M. S., Han, X., Ando, K., Hedou, J. J., Feyaerts, D., Peterson, L. S., Rumer, K. K., Tsai, E. S., Ganio, E. A., Gaudilliere, D. K., Tsai, A. S., Choisy, B., Gaigne, L. P., Verdonk, F., Jacobsen, D., Gavasso, S., Traber, G. M., Ellenberger, M., Stanley, N., Becker, M., Culos, A., Fallahzadeh, R., Wong, R. J., Darmstadt, G. L., Druzin, M. L., Winn, V. D., Gibbs, R. S., Ling, X. B., Sylvester, K., Carvalho, B., Snyder, M. P., Shaw, G. M., Stevenson, D. K., Contrepois, K., Angst, M. S., Aghaeepour, N., Gaudilliere, B. 2021; 13 (592)


    Estimating the time of delivery is of high clinical importance because pre- and postterm deviations are associated with complications for the mother and her offspring. However, current estimations are inaccurate. As pregnancy progresses toward labor, major transitions occur in fetomaternal immune, metabolic, and endocrine systems that culminate in birth. The comprehensive characterization of maternal biology that precedes labor is key to understanding these physiological transitions and identifying predictive biomarkers of delivery. Here, a longitudinal study was conducted in 63 women who went into labor spontaneously. More than 7000 plasma analytes and peripheral immune cell responses were analyzed using untargeted mass spectrometry, aptamer-based proteomic technology, and single-cell mass cytometry in serial blood samples collected during the last 100 days of pregnancy. The high-dimensional dataset was integrated into a multiomic model that predicted the time to spontaneous labor [R = 0.85, 95% confidence interval (CI) [0.79 to 0.89], P = 1.2 * 10-40, N = 53, training set; R = 0.81, 95% CI [0.61 to 0.91], P = 3.9 * 10-7, N = 10, independent test set]. Coordinated alterations in maternal metabolome, proteome, and immunome marked a molecular shift from pregnancy maintenance to prelabor biology 2 to 4 weeks before delivery. A surge in steroid hormone metabolites and interleukin-1 receptor type 4 that preceded labor coincided with a switch from immune activation to regulation of inflammatory responses. Our study lays the groundwork for developing blood-based methods for predicting the day of labor, anchored in mechanisms shared in preterm and term pregnancies.

    View details for DOI 10.1126/scitranslmed.abd9898

    View details for PubMedID 33952678

  • Intravenous oxytocin dosing regimens for postpartum hemorrhage prevention at cesarean section: a systematic review and meta-analysis. American journal of obstetrics and gynecology Phung, L. C., Farrington, E. K., Connolly, M., Wilson, A. N., Carvalho, B., Homer, C. S., Vogel, J. P. 2021


    OBJECTIVE: To synthesize available evidence on intravenous (IV) oxytocin dosing regimens for the prevention of postpartum hemorrhage (PPH) at cesarean section (CS).DATA SOURCES: We searched Medline/OVID, Embase, Global Index Medicus, CINAHL, CENTRAL, ClinicalTrials.gov, and ICTRP for eligible studies published until Feb 2020.STUDY ELIGIBILITY CRITERIA: We included any randomized or non-randomized study published in peer-reviewed journals that compared at least two different dosing regimens of IV oxytocin for PPH prevention in women undergoing CS.STUDY APPRAISAL AND SYNTHESIS METHODS: Two authors independently assessed eligibility, extracted data, and assessed risk of bias. Primary outcome was incidence of PPH ≥ 1000 mL. Other review outcomes included use of additional uterotonics, blood loss, and adverse maternal events. Data were analyzed based on type of IV administration (bolus only, infusion only, bolus plus infusion) and oxytocin dose. Meta-analysis was performed using randomized trials and reported using risk ratios or mean difference with 95% confidence intervals. GRADE was used to rate the certainty of evidence. Findings from dose-finding trials and non-randomized studies were reported narratively.RESULTS: Thirty-five studies (7,333 women) met our inclusion criteria, including 30 randomized trials and five non-randomized studies. There were limited data from trials for most outcomes, and results were not conclusive. Compared to bolus plus infusion regimens, bolus only regimens probably result in slightly higher mean blood loss (MD 52 mL, 95% CI 0.4-104 mL, moderate certainty). Amongst bolus plus infusion regimens, initial bolus doses < 5 IU may reduce nausea (RR 0.26, 95% CI 0.11-0.63, low certainty) as compared to 5-9 IU. Total oxytocin doses 5-9 IU versus 10-19 IU may increase use of additional uterotonics (RR 13.00, 95% CI 1.75-96.37, low certainty). Effects on other outcomes were generally inconclusive.CONCLUSION: There are limited data comparing IV oxytocin regimens for PPH prevention at CS. Bolus plus infusion regimens may lead to minor reductions in mean blood loss, and initial bolus doses of < 5 IU may minimize nausea. Bolus only regimens of 10 IU versus 5 IU may decrease use of additional uterotonics, however further comparative trials are required to understand effects on other key outcomes, particularly hypotension.

    View details for DOI 10.1016/j.ajog.2021.04.258

    View details for PubMedID 33957113

  • An observational pilot study of a novel loss of resistance syringe for locating the epidural space. International journal of obstetric anesthesia Athar, M. W., Guo, N., Ortner, C., Carvalho, B., Abir, G., Riley, E. T. 2021: 102984


    BACKGROUND: The EpiFaith syringe is a novel loss-of-resistance syringe that utilizes a spring-loaded plunger that automatically moves forward within the syringe when there is a loss of resistance. We evaluated the syringe in a clinical setting, among a cohort of pregnant women receiving neuraxial labor analgesia.METHODS: In a non-randomized, observational study, four anesthesiologists used the EpiFaith syringe 10 times each while placing epidural catheters for labor analgesia. The anesthesiologists scored each placement on an 11-point Likert scale (-5 = absolutely worse, 0 = the same, and 5 = absolutely better than using their regular loss-of-resistance syringe technique).RESULTS: All 40 neuraxial placements correctly located the epidural space. Air was used in the syringe in 35 of the 40 cases. In 50%, 27.5% and 22.5% of cases the anesthesiologists reported that using the EpiFaith syringe was better than, the same as, or worse than using their regular syringe, respectively. There were no inadvertent dural punctures.CONCLUSIONS: This feasibility study found that three of the four anesthesiologists scored the EpiFaith syringe as better or the same as using their regular loss-of-resistance syringe. More extensive studies are required to determine if the EpiFaith syringe reduces adverse outcomes such as unintentional dural punctures.

    View details for DOI 10.1016/j.ijoa.2021.102984

    View details for PubMedID 33994273

  • Superficial Cervical Plexus Block for Awake Large-Bore Central Line Placement in Parturients: A Case Series. A&A practice Sheikh, M., Carvalho, B., Boublik, J., Ansari, J. 2021; 15 (3): e01429


    Pregnant patients with high-risk conditions including abnormal placentation or severe cardiovascular disease may require large-bore central venous access at the time of delivery. Central lines are generally inserted while obstetric patients are awake, either because neuraxial anesthesia is planned or to minimize fetal exposure to anesthetic medications. Despite local infiltration, the procedure can cause significant patient discomfort. This case series describes use of a superficial cervical plexus block (SCPB) to facilitate line placement in 4 pregnant women with high-risk conditions. SCPB is technically straightforward with low reported complication rates and should be considered for pregnant patients requiring large-bore central lines.

    View details for DOI 10.1213/XAA.0000000000001429

    View details for PubMedID 33740791

  • Point-of-Care Lung Ultrasound Pattern in Healthy Parturients: Prevalence of Pulmonary Interstitial Syndrome Following Vaginal Delivery, Elective and Unplanned Intrapartum Cesarean Delivery. Anesthesia and analgesia Macias, P. n., Wilson, J. G., Austin, N. S., Guo, N. n., Carvalho, B. n., Ortner, C. M. 2021


    Pregnancy-related cardiovascular physiologic changes increase the likelihood of pulmonary edema, with the risk of fluid extravasating into the pulmonary interstitium being potentially at a maximum during the early postpartum period. Data on the impact of labor and peripartum hemodynamic strain on lung ultrasound (LUS) are limited, and the prevalence of subclinical pulmonary interstitial syndrome in peripartum women is poorly described. The primary aim of this exploratory study was to estimate the prevalence of pulmonary interstitial syndrome in healthy term parturients undergoing vaginal (VD), elective (eCD), and unplanned intrapartum cesarean deliveries (uCD). Secondary aims were to estimate the prevalence of positive lung regions (≥3 B-lines on LUS per region) and to assess the associations between positive lung regions and possible contributing factors.In this prospective observational cohort study, healthy women at term undergoing VD, eCD, or uCD were enrolled. Following international consensus recommendations, a LUS examination was performed within 4 hours after delivery applying an 8-region technique. Pulmonary interstitial syndrome was defined by the presence of 2 or more positive lung regions per hemithorax. Ultrasound studies were reviewed by 2 blinded reviewers and assessed for interobserver reliability.Seventy-five women were assessed (n = 25 per group). No pulmonary interstitial syndrome was found in the VD and eCD groups (each 0 of 25; 0%, 95% confidence interval [CI], 0-13.7). Pulmonary interstitial syndrome was found in 2 of 25 (8%, 95% CI, 1-26) women undergoing an uCD (P = .490 for VD versus uCD and P = .490 for eCD versus uCD). In 1 woman, this correlated clinically with the development of pulmonary edema. One or more positive lung regions were present in 5 of 25 (20%), 6 of 25 (24%), and 11 of 25 (44%) parturients following VD, eCD, and uCD, respectively (P = .136). Positive lung regions were predominantly found in lateral lung regions. The number of positive lung regions showed a weak correlation with patient age (r = 0.25, 95% CI, 0.05-0.47; P = .033). No significant association was found between LUS pattern and parity, duration of labor, labor augmentation, labor induction, estimated total intravenous fluid intake, or net intravenous fluid intake.Although many focal areas of increased extravascular lung water (20%-44% prevalence) can be identified on LUS, the overall prevalence of pulmonary interstitial syndrome was 2.7% (2 of 75; 95% CI, 0.3-9.3) among healthy term parturients soon after delivery. Focal areas of positive lung water regions were weakly correlated with maternal age.

    View details for DOI 10.1213/ANE.0000000000005464

    View details for PubMedID 33721873

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