Monitoring the safety of COVID-19 vaccination in pregnancy in the UK: A national study using the UK Obstetric Surveillance System (UKOSS), UK Teratology Information Service (UKTIS) and Vaccination in Pregnancy (VIP) safety monitoring systems.

Background: COVID-19 vaccines are protective against disease. Pregnant women benefit from vaccination as they are at higher risk of poor maternal and neonatal outcomes following infection. Methods: Following regulatory approval of two COVID-19 vaccines in the United Kingdom, a rapid national study of vaccination in pregnancy was instituted using three existing safety surveillance platforms: UKOSS, UKTIS and VIP. This preliminary report describes the data collected up to the 15th June 2021. Results: There were 971 reports of COVID-19 vaccination in the UKOSS/UKTIS (n = 493) and VIP (n = 478) monitoring systems describing 908 individual pregnancies. Pfizer-BioNTech mRNA vaccination was most common (n = 501, 55.2%), most women were vaccinated in their second or third trimester (n = 566, 62.3%), and were mainly vaccinated due to occupational infection risk (n = 577, 63.5%). Conclusion: Obstetric outcome data will be obtained by December 2021. However, women should not delay vaccination whilst awaiting further safety data to emerge.

Monitoring the safety of COVID-19 vaccination in pregnancy in the UK: A national study using the UK Obstetric Surveillance System (UKOSS), UK Teratology Information Service (UKTIS) and Vaccination in Pregnancy (VIP) safety monitoring systems

Background COVID-19 vaccines are protective against disease. Pregnant women benefit from vaccination as they are at higher risk of poor maternal and neonatal outcomes following infection. Methods Following regulatory approval of two COVID-19 vaccines in the United Kingdom, a rapid national study of vaccination in pregnancy was instituted using three existing safety surveillance platforms: UKOSS, UKTIS and VIP. This preliminary report describes the data collected up to the 15th June 2021. Results There were 971 reports of COVID-19 vaccination in the UKOSS/UKTIS (n = 493) and VIP (n = 478) monitoring systems describing 908 individual pregnancies. Pfizer-BioNTech mRNA vaccination was most common (n = 501, 55.2%), most women were vaccinated in their second or third trimester (n = 566, 62.3%), and were mainly vaccinated due to occupational infection risk (n = 577, 63.5%). Conclusion Obstetric outcome data will be obtained by December 2021. However, women should not delay vaccination whilst awaiting further safety data to emerge.

Severity of maternal SARS-CoV-2 infection and perinatal outcomes of women admitted to hospital during the omicron variant dominant period using UK Obstetric Surveillance System data: prospective, national cohort study

Objectives To describe the severity of maternal infection when the omicron SARS-CoV-2 variant (B.1.1.529) was dominant (15 December 2021 to 14 March 2022) and describe outcomes by symptoms and vaccination status. Design Prospective, national cohort study using the UK Obstetric Surveillance System. Setting 94 hospitals in the UK with a consultant led maternity unit. Participants Pregnant women admitted to hospital for any cause with a positive SARS-CoV-2 test. Main outcome measures Symptomatic or asymptomatic infection, vaccination status by doses before admission, and severity of maternal infection (moderate or severe infection according to modified World Health Organization's criteria). Results Of 3699 women who were admitted to hospital, 986 (26.7%, 95% confidence interval 25.3% to 28.1%) had symptoms;of these, 144 (14.6%, 12.5% to 17.0%) had a moderate to severe infection, 99 (10.4%, 8.6% to 12.5%) of 953 received respiratory support, and 30 (3.0%, 2.1% to 4.3%) were admitted to an intensive care unit. Covid-19 specific drug treatment was given to 13 (43.3%) of the 30 women in intensive care. Four women with symptoms died (0.4%, 0.1% to 1.1%). Vaccination status was known for 845 (85.6%) women with symptoms;489 (58.9%) were unvaccinated and only 55 (6.5%) had three doses. Moderate to severe infection was reported for 93 (19.0%) of 489 unvaccinated women with symptoms, decreasing to three (5.5%) of 55 after three doses. Among the 30 women with symptoms who were admitted to intensive care, 23 (76.7%) were unvaccinated and none had received three doses. Conclusion Most women with severe covid-19 disease were unvaccinated and vaccine coverage among pregnant women admitted to hospital with SARS-CoV-2 was low. Ongoing action to prioritise and advocate for vaccine uptake in pregnancy is essential. A better understanding of the persistent low use of drug treatments is an urgent priority. Trial registration ISRCTN 40092247.

Severity of maternal infection and perinatal outcomes during periods of SARS-CoV-2 wildtype, alpha, and delta variant dominance in the UK: prospective cohort study

Objective To compare the severity of maternal infection and perinatal outcomes during periods in which wildtype, alpha variant, and delta variant of SARS-CoV-2 were dominant in the UK. Design Prospective cohort study. Setting 194 obstetric units across the UK, during the following periods: between 1 March and 30 November 2020 (wildtype dominance), between 1 December 2020 and 15 May 2021 (alpha variant dominance), and between 16 May and 31 October 2021 (delta variant dominance). Participants 4436 pregnant women admitted to hospital with covid-19 related symptoms. Main outcome measures Moderate to severe maternal SARS-CoV-2 infection (indicated by any of the following: oxygen saturation <95% on admission, need for oxygen treatment, evidence of pneumonia on imaging, admission to intensive care, or maternal death), and pregnancy and perinatal outcomes (including mode and gestation of birth, stillbirth, live birth, admission to neonatal intensive care, and neonatal death). Results 1387, 1613, and 1436 pregnant women were admitted to hospital with covid-19 related symptoms during the wildtype, alpha, and delta dominance periods, respectively;of these women, 340, 585, and 614 had moderate to severe infection, respectively. The proportion of pregnant women admitted with moderate to severe infection increased during the subsequent alpha and delta dominance periods, compared with the wildtype dominance period (wildtype 24.5% v alpha 36.2% (adjusted odds ratio 1.98, 95% confidence interval 1.66% to 2.37%);wildtype 24.5% v delta 42.8% (2.66, 2.21 to 3.20)). Compared with the wildtype dominance period, women admitted during the alpha dominance period were significantly more likely to have pneumonia, require respiratory support, and be admitted to intensive care;these three risks were even greater during the delta dominance period (wildtype v delta: pneumonia, adjusted odds ratio 2.52, 95% confidence interval 2.06 to 3.09;respiratory support, 1.90, 1.52 to 2.37;and intensive care, 2.71, 2.06 to 3.56). Of 1761 women whose vaccination status was known, 38 (2.2%) had one dose and 16 (1%) had two doses before their diagnosis (of whom 14 (88%) had mild infection). The proportion of women receiving drug treatment for SARS-CoV-2 management was low, but did increase between the wildtype dominance period and the alpha and delta dominance periods (10.4% wildtype v 14.9% alpha (2.74, 2.08 to 3.60);10.4% wildtype v 13.6% delta (2.54, 1.90 to 3.38)). Conclusions While limited by the absence of variant sequencing data, these findings suggest that during the periods when the alpha and delta variants of SARS-CoV-2 were dominant, covid-19 was associated with more severe maternal infection and worse pregnancy outcomes than during the wildtype dominance period. Most women admitted with SARS-CoV-2 related symptoms were unvaccinated. Urgent action to prioritise vaccine uptake in pregnancy is essential. Study registration ISRCTN40092247.

Neonatal outcomes of maternal SARS-CoV-2 infection in the UK: a prospective cohort study using active surveillance.

BACKGROUND: Newborns may be affected by maternal SARS-CoV-2 infection during pregnancy. We aimed to describe the epidemiology, clinical course and short-term outcomes of babies admitted to a neonatal unit (NNU) following birth to a mother with confirmed SARS-CoV-2 infection within 7 days of birth. METHODS: This is a UK prospective cohort study; all NHS NNUs, 1 March 2020 to 31 August 2020. Cases were identified via British Paediatric Surveillance Unit with linkage to national obstetric surveillance data. Reporting clinicians completed data forms. Population data were extracted from the National Neonatal Research Database. RESULTS: A total of 111 NNU admissions (1.98 per 1000 of all NNU admissions) involved 2456 days of neonatal care (median 13 [IQR 5, 34] care days per admission). A total of 74 (67%) babies were preterm. In all, 76 (68%) received respiratory support; 30 were mechanically ventilated. Four term babies received therapeutic hypothermia for hypoxic ischaemic encephalopathy. Twenty-eight mothers received intensive care, with four dying of COVID-19. Eleven (10%) babies were SARS-CoV-2 positive. A total of 105 (95%) babies were discharged home; none of the three deaths before discharge was attributed to SARS-CoV-2. CONCLUSION: Babies born to mothers with SARS-CoV-2 infection around the time of birth accounted for a low proportion of total NNU admissions over the first 6 months of the UK pandemic. Neonatal SARS-CoV-2 was uncommon. STUDY REGISTRATION: ISRCTN60033461; protocol available at http://www.npeu.ox.ac.uk/pru-mnhc/research-themes/theme-4/covid-19 . IMPACT: Neonatal unit admissions of babies born to mothers with SARS-CoV-2 infection comprised only a small proportion of total neonatal admissions in the first 6 months of the pandemic. A high proportion of babies requiring neonatal admission who were born to mothers with confirmed SARS-CoV-2 infection were preterm and had neonatal SARS-CoV-2 infection and/or other conditions associated with long-term sequelae. Adverse neonatal conditions were more common in babies whose SARS-CoV-2-positive mothers required intensive care compared to those whose SARS-CoV-2-positive mothers who did not.

Clinical risk factors of adverse outcomes among women with COVID-19 in the pregnancy and postpartum period: A sequential, prospective meta-analysis.

OBJECTIVE: This sequential, prospective meta-analysis (sPMA) sought to identify risk factors among pregnant and postpartum women with COVID-19 for adverse outcomes related to: disease severity, maternal morbidities, neonatal mortality and morbidity, adverse birth outcomes. DATA SOURCES: We prospectively invited study investigators to join the sPMA via professional research networks beginning in March 2020. STUDY ELIGIBILITY CRITERIA: Eligible studies included those recruiting at least 25 consecutive cases of COVID-19 in pregnancy within a defined catchment area. STUDY APPRAISAL AND SYNTHESIS METHODS: We included individual patient data from 21 participating studies. Data quality was assessed, and harmonized variables for risk factors and outcomes were constructed. Duplicate cases were removed. Pooled estimates for the absolute and relative risk of adverse outcomes comparing those with and without each risk factor were generated using a two-stage meta-analysis. RESULTS: We collected data from 33 countries and territories, including 21,977 cases of SARS-CoV-2 infection in pregnancy or postpartum. We found that women with comorbidities (pre-existing diabetes, hypertension, cardiovascular disease) versus those without were at higher risk for COVID-19 severity and pregnancy health outcomes (fetal death, preterm birth, low birthweight). Participants with COVID-19 and HIV were 1.74 times (95% CI: 1.12, 2.71) more likely to be admitted to the ICU. Pregnant women who were underweight before pregnancy were at higher risk of ICU admission (RR 5.53, 95% CI: 2.27, 13.44), ventilation (RR 9.36, 95% CI: 3.87, 22.63), and pregnancy-related death (RR 14.10, 95% CI: 2.83, 70.36). Pre-pregnancy obesity was also a risk factor for severe COVID-19 outcomes including ICU admission (RR 1.81, 95% CI: 1.26,2.60), ventilation (RR 2.05, 95% CI: 1.20,3.51), any critical care (RR 1.89, 95% CI: 1.28,2.77), and pneumonia (RR 1.66, 95% CI: 1.18,2.33). Anemic pregnant women with COVID-19 also had increased risk of ICU admission (RR 1.63, 95% CI: 1.25, 2.11) and death (RR 2.36, 95% CI: 1.15, 4.81). CONCLUSION: We found that pregnant women with comorbidities including diabetes, hypertension, and cardiovascular disease were at increased risk for severe COVID-19-related outcomes, maternal morbidities, and adverse birth outcomes. We also identified several less commonly-known risk factors, including HIV infection, pre-pregnancy underweight, and anemia. Although pregnant women are already considered a high-risk population, special priority for prevention and treatment should be given to pregnant women with these additional risk factors.

Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.

INTRODUCTION: Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies. METHODS: We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale. RESULTS: We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias. CONCLUSIONS: This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol.

Protocol for a sequential, prospective meta-analysis to describe coronavirus disease 2019 (COVID-19) in the pregnancy and postpartum periods.

We urgently need answers to basic epidemiological questions regarding SARS-CoV-2 infection in pregnant and postpartum women and its effect on their newborns. While many national registries, health facilities, and research groups are collecting relevant data, we need a collaborative and methodologically rigorous approach to better combine these data and address knowledge gaps, especially those related to rare outcomes. We propose that using a sequential, prospective meta-analysis (PMA) is the best approach to generate data for policy- and practice-oriented guidelines. As the pandemic evolves, additional studies identified retrospectively by the steering committee or through living systematic reviews will be invited to participate in this PMA. Investigators can contribute to the PMA by either submitting individual patient data or running standardized code to generate aggregate data estimates. For the primary analysis, we will pool data using two-stage meta-analysis methods. The meta-analyses will be updated as additional data accrue in each contributing study and as additional studies meet study-specific time or data accrual thresholds for sharing. At the time of publication, investigators of 25 studies, including more than 76,000 pregnancies, in 41 countries had agreed to share data for this analysis. Among the included studies, 12 have a contemporaneous comparison group of pregnancies without COVID-19, and four studies include a comparison group of non-pregnant women of reproductive age with COVID-19. Protocols and updates will be maintained publicly. Results will be shared with key stakeholders, including the World Health Organization (WHO) Maternal, Newborn, Child, and Adolescent Health (MNCAH) Research Working Group. Data contributors will share results with local stakeholders. Scientific publications will be published in open-access journals on an ongoing basis.

Effect of SARS-CoV-2 infection in neonates or in pregnancy on developmental outcomes at 21-24 months (SINEPOST): study protocol for a prospective cohort study.

INTRODUCTION: Exposure to SARS-CoV-2 during pregnancy or in the neonatal period may impact fetal or neonatal brain development either through direct central nervous system infection or indirectly through the adverse effects of viral infection-related inflammation in the mother or newborn infant. This study aims to determine whether there are early neurodevelopmental effects of SARS-CoV-2 infection. METHODS AND ANALYSIS: We will conduct a prospective national population-based cohort study of children aged 21-24 months who were born at term (≥37 weeks' gestation) between 1 March 2020 and 28 February 2021 and were either antenatally exposed, neonatally exposed or unexposed (comparison cohort) to SARS-CoV-2. Nationally, hospitals will identify and approach parents of children eligible for inclusion in the antenatally and neonatally exposed cohorts using information from the UK Obstetric Surveillance System (UKOSS) and British Paediatric Surveillance Unit (BPSU) national surveillance studies and will identify and approach eligible children for the comparison cohort through routine birth records. Parents will be asked to complete questionnaires to assess their child's development at 21-24 months of age. Outcome measures comprise the Ages and Stages Questionnaire, Third Edition (ASQ-3), Ages and Stages Questionnaire Social-Emotional, Second Edition (ASQ-SE-2), Liverpool respiratory symptoms questionnaire and questionnaire items to elicit information about healthcare usage. With parental consent, study data will be linked to routine health and education records for future follow-up. Regression models will compare ASQ-3 and ASQ-SE-2 scores and proportions, frequency of respiratory symptoms and healthcare usage between the exposed and comparison cohorts, adjusting for potential confounders. ETHICS AND DISSEMINATION: Ethics approval was obtained from the London-Westminster Research Ethics Committee. Findings will be disseminated in scientific conference presentations and peer-reviewed publications. ISRCTN REGISTRATION NUMBER: ISRCTN99910769.

Effect of SARS-CoV-2 infection in neonates or in pregnancy on developmental outcomes at 21–24 months (SINEPOST): study protocol for a prospective cohort study

Introduction Exposure to SARS-CoV-2 during pregnancy or in the neonatal period may impact fetal or neonatal brain development either through direct central nervous system infection or indirectly through the adverse effects of viral infection-related inflammation in the mother or newborn infant. This study aims to determine whether there are early neurodevelopmental effects of SARS-CoV-2 infection. Methods and analysis We will conduct a prospective national population-based cohort study of children aged 21–24 months who were born at term (≥37 weeks’ gestation) between 1 March 2020 and 28 February 2021 and were either antenatally exposed, neonatally exposed or unexposed (comparison cohort) to SARS-CoV-2. Nationally, hospitals will identify and approach parents of children eligible for inclusion in the antenatally and neonatally exposed cohorts using information from the UK Obstetric Surveillance System (UKOSS) and British Paediatric Surveillance Unit (BPSU) national surveillance studies and will identify and approach eligible children for the comparison cohort through routine birth records. Parents will be asked to complete questionnaires to assess their child’s development at 21–24 months of age. Outcome measures comprise the Ages and Stages Questionnaire, Third Edition (ASQ-3), Ages and Stages Questionnaire Social-Emotional, Second Edition (ASQ-SE-2), Liverpool respiratory symptoms questionnaire and questionnaire items to elicit information about healthcare usage. With parental consent, study data will be linked to routine health and education records for future follow-up. Regression models will compare ASQ-3 and ASQ-SE-2 scores and proportions, frequency of respiratory symptoms and healthcare usage between the exposed and comparison cohorts, adjusting for potential confounders. Ethics and dissemination Ethics approval was obtained from the London-Westminster Research Ethics Committee. Findings will be disseminated in scientific conference presentations and peer-reviewed publications. ISRCTN registration number ISRCTN99910769.

Neonatal complications of SARS-CoV-2 infection in the UK: a prospective national cohort study using active surveillance

1206 Figure 1Weekly number of neonates admitted who have confirmed SARS-CoV-2 by date of diagnosis, UK, 1st March 2020 to 7th November 2021[Figure omitted. See PDF] 1206 Table 1Maternal and neonatal mortality in association with SARS-CoV-2 infection, UK 01/03/2020-31/10/2021ConclusionUsing population level surveillance data we describe neonatal complications directly and indirectly attributable to SARS-CoV-2 infection during the first three pandemic waves. This study demonstrates the low risk to neonates despite the emergence of new variants. Continued surveillance will allow the impacts of new variants on the neonatal population to be characterised.ReferencesGale C, Quigley MA, Placzek A, et al. Characteristics and outcomes of neonatal SARS-CoV-2 infection in the UK: a prospective national cohort study using active surveillance. Lancet Child Adolesc Heal 2021;5:113–21.Vousden N, Ramakrishnan R, Bunch K, et al. Impact of SARS-CoV-2 variant on the severity of maternal infection and perinatal outcomes: Data from the UK Obstetric Surveillance System national cohort. Medrvix 2021. doi:10.1101/2021.07.22.21261000.Knight M, Kurinczuk JJ, Tuffnell D, Brocklehurst P. The UK Obstetric Surveillance System for raredisorders of pregnancy. BJOG An Int J Obstet Gynaecol 2005;112:263–5.

Diagnosis and management of covid-19 in pregnancy.

Pregnant women with covid-19 are at greater risk of severe disease than their non-pregnant peers, and yet they are frequently denied investigations or treatments because of unfounded concerns about risk to the fetus. The basic principles of diagnosing and managing covid-19 are the same as for non-pregnant patients, and a multidisciplinary, expert team approach is essential to ensure optimal care. During pregnancy, treatment with corticosteroids should be modified to use non-fluorinated glucocorticoids. Il-6 inhibitors and monoclonal antibodies, together with specific antiviral therapies, may also be considered. Prophylaxis against venous thromboembolism is important. Women may require respiratory support with oxygen, non-invasive ventilation, ventilation in a prone position (either awake or during invasive ventilation), intubation and ventilation, and extracorporeal membrane oxygenation (ECMO). Pregnancy is not a contraindication for any of these supportive therapies, and the criteria for providing them are the same as in the general population. Decisions regarding timing, place, and mode of delivery should be taken with a multidisciplinary team including obstetricians, physicians, anesthetists, and intensivists experienced in the care of covid-19 in pregnancy. Ideally these decisions should take place in consultation with centers that have experience and expertise in all these specialties.

Long COVID (post-COVID-19 condition) in children: a modified Delphi process.

OBJECTIVE: The aim of this study was to derive a research definition for 'Long COVID (post-COVID-19 condition)' in children and young people (CYP) to allow comparisons between research studies. DESIGN: A three-phase online Delphi process was used, followed by a consensus meeting. Participants were presented with 49 statements in each phase and scored them from 1 to 9 based on how important they were for inclusion in the research definition of Long COVID in CYP. The consensus meeting was held to achieve representation across the stakeholder groups. Statements agreed at the consensus meeting were reviewed by participants in the Patient and Public Involvement (PPI) Research Advisory Group. SETTING: The study was conducted remotely using online surveys and a virtual consensus meeting. PARTICIPANTS: 120 people with relevant expertise were divided into three panels according to their area of expertise: Service Delivery, Research (or combination of research and service delivery) and Lived Experience. The PPI Research Advisory group consisted of CYP aged 11-17 years. MAIN OUTCOME MEASURES: Consensus was defined using existing guidelines. If consensus was achieved in two or more panels or was on the border between one and two panels, those statements were discussed and voted on at the consensus meeting. RESULTS: Ten statements were taken forward for discussion in the consensus meeting and five statements met threshold to be included in the research definition of Long COVID among CYP. The research definition, aligned to the clinical case definition of the WHO, is proposed as follows: Post-COVID-19 condition occurs in young people with a history of confirmed SARS-CoV-2 infection, with at least one persisting physical symptom for a minimum duration of 12 weeks after initial testing that cannot be explained by an alternative diagnosis. The symptoms have an impact on everyday functioning, may continue or develop after COVID infection, and may fluctuate or relapse over time. The positive COVID-19 test referred to in this definition can be a lateral flow antigen test, a PCR test or an antibody test. CONCLUSIONS: This is the first research definition of Long COVID (post-COVID-19 condition) in CYP and complements the clinical case definition in adults proposed by the WHO.

Feasibility of establishing a Canadian Obstetric Survey System (CanOSS) for severe maternal morbidity: a study protocol.

INTRODUCTION: Severe maternal morbidity (SMM)-an unexpected pregnancy-associated maternal outcome resulting in severe illness, prolonged hospitalisation or long-term disability-is recognised by many, as the preferred indicator of the quality of maternity care, especially in high-income countries. Obtaining comprehensive details on events and circumstances leading to SMM, obtained through maternity units, could complement data from large epidemiological studies and enable targeted interventions to improve maternal health. The aim of this study is to assess the feasibility of gathering such data from maternity units across Canadian provinces and territories, with the goal of establishing a national obstetric survey system for SMM in Canada. METHODS AND ANALYSIS: We propose a sequential explanatory mixed-methods study. We will first distribute a cross-sectional survey to leads of all maternity units across Canada to gather information on (1) Whether the unit has a system for reviewing SMM and the nature and format of this system, (2) Willingness to share anonymised data on SMM by direct entry using a web-based platform and (3) Respondents' perception on the definition and leading causes of SMM at a local level. This will be followed by semistructured interviews with respondent groups defined a priori, to identify barriers and facilitators for data sharing. We will perform an integrated analysis to determine feasibility outcomes, a narrative description of barriers and facilitators for data-sharing and resource implications for data acquisition on an annual basis, and variations in top-5 causes of SMM. ETHICS AND DISSEMINATION: The study has been approved by the Mount Sinai and Hamilton Integrated Research Ethics Boards. The study findings will be presented at annual scientific meetings of the Society of Obstetricians and Gynaecologists of Canada, North American Society of Obstetric Medicine, and International Network of Obstetric Survey Systems and published in an open-access peer-reviewed Obstetrics and Gynaecology or General Internal Medicine journal.