This section below summarizes scientific evidence and jurisdictional guidance/experiences regarding COVID-19 in obstetrical patients, including incidence, severity, outcomes, and management.

The majority of the information presented is taken directly from the identified sources. In particular, the following topics are reviewed:

• Incidence: Rates of SARS-CoV-2 infection among pregnant women across trimesters, and how this compares to the general population and to non-pregnant women of reproductive age.
• Severity: Rates of hospital admission, intensive care unit (ICU) admission, and mechanical ventilation amongst pregnant women with SARS-CoV-2 infection and how it compares to the general population and to non-pregnant women of reproductive age.
• Outcomes: Outcomes of hospitalized and critically ill pregnant patients with SARS-CoV-2 infection, including ICU mortality, hospital mortality, ICU length of stay, hospital length of stay, pre- term delivery, emergent delivery, and admission of baby to neonatal intensive care (NICU).
• Management: The unique management considerations for pregnant women hospitalized with COVID-19 respiratory failure compared to the general hospitalized COVID-19 population, including ward or critical care, use of prone positioning, safety profile of medications (particularly remdesivir, tocilizumab, and sarilumab), delivery protocols, and organizational considerations.

The following limitations should be noted:

• Because of the extensive amount of literature available on these topics, the scientific evidence searches were limited to systematic reviews, meta-analyses, and reviews. However, some individual studies were included if identified and relevant.
• The majority of the information presented contains clinical outcomes and guidance; these recommendations are those of the authors of the original studies and the Research, Analysis, and Evaluation Branch does not have the expertise to evaluate such recommendations.
• The methodological quality of all the sources identified are unclear as they have not been assessed.
• No information was identified on how the emergence of COVID-19 variants of concern have impacted the incidence, severity, outcomes, and management of pregnant patients with COVID-19.

Scientific Evidence

• Incidence: Findings from 13 sources suggest that the population prevalence of COVID-19 among pregnant women is difficult to estimate given geographic and temporal variability in the prevalence of COVID-19 and differing thresholds for testing pregnant women. There seems to be a higher risk of COVID-19 in the third trimester in pregnant women compared to the first and second trimesters. The symptomatic infection in pregnant women generally seems to be of lower incidence compared to the general population, and there are high rates of asymptomatic infection in pregnant women. Similar to data from the general population internationally, SARS-CoV-2 infection may be higher in pregnant women who are racial/ethnic minorities, uninsured, low income, or from neighborhoods with low income, high crowding, or increased density. For example: 
  • The PregCOV-19 living systematic review and meta-analysis (Sept 1, 2020) of 73 international studies with 67,271 women found that 10% of pregnant and recently pregnant women attending or admitted to hospital for any reason were diagnosed as having suspected or confirmed COVID-19.
  • A US Centers for Disease Control and Prevention (CDC) study (Nov 6, 2020) assessed data from the National Notifiable Diseases Surveillance System of 1,300,938 women aged 15-44 years with laboratory results indicative of acute infection with SARS-CoV-2. Data on pregnancy status were available for 461,825 (35.5%) women with laboratory-confirmed infection, 409,462 (88.7%) of whom were symptomatic. Among symptomatic women, 23,434 (5.7%) were reported to be pregnant. 
  • A review (May 2021) of 196 studies noted that, in Europe, estimates of COVID-19 prevalence differed based on region and time period, ranging from 0.6% in Lombardy (Italy) in early March 2020 to 7.0% in London during the same period. Multiple studies on universal screening programs have also confirmed high rates of asymptomatic or pre-symptomatic disease, ranging from 61.5% of women with a positive test in Belgium to 85-90% in areas of London and New York City.

• Severity: There is mixed evidence from 40 sources on the severity of COVID-19 in pregnant women: some studies report that pregnant status raises the morbidity of COVID-19 (e.g., ICU admission, mechanical ventilation), while others indicate that the clinical presentation of COVID-19 in pregnant women resembles that of non-pregnant women, which generally includes mild cough, breathlessness, and fever. Some studies suggest that certain factors (e.g., increased maternal age, obesity, pre-existing comorbidities, pre-eclampsia) are associated with severe COVID-19 in pregnancy. For example: 
  • A systematic review and meta-analysis (Jan 2021) noted that the pooled prevalence of ICU admission and death among pregnant women with COVID-19 were comparable with those reported in non-pregnant women.
  • A systematic review and meta-analysis (Jan 2, 2021) found pregnant patients present with similar clinical characteristics of COVID-19 when compared with the general population, but they may be more asymptomatic.
  • A review of systematic reviews (Jan 2021) estimated that maternal ICU admission and mechanical ventilation rates of pregnant women with COVID-19 were 3–10% and 1.4–5.5%, respectively, after accounting for the quality of studies. Reported maternal ICU admission, mechanical ventilation, and mortality rates of pregnant women with COVID-19 were high when compared with non-pregnant women. A possible interpretation of this finding was the existence of other comorbidities accompanying pregnancy, compared with non-pregnant women at a similar age.
  • A study (Feb 20, 2021) by the World Association of Perinatal Medicine Working Group on COVID-19 examined high- and low-risk pregnancies complicated by severe COVID-19 infection from 76 centres from 25 countries. The risk of composite adverse maternal outcomes (i.e., maternal mortality and morbidity, including ICU admission, use of mechanical ventilation, or death) was higher in high-risk pregnancies than in low-risk pregnancies. Pregnancies were considered high-risk in case of either pre-existing chronic medical conditions in pregnancy (i.e., pregestational diabetes mellitus, chronic hypertension, or autoimmune disease) or obstetrical disorders occurring in pregnancy (i.e., preeclampsia, gestational hypertension, or gestational diabetes mellitus).
  • The INTERCOVID multinational study (Apr 22, 2021) involving 43 institutions across 18 countries found pregnant women with a COVID-19 diagnosis were associated with a greater risk of admission to ICU and referral to a higher level of care. Among all ICU admissions, women with COVID-19 diagnosis stayed 3.73 days longer than pregnant women without COVID-19.
  • A systematic review and meta-analysis (Mar 24, 2021) found that the proportions of mechanical ventilation support (2%, 4%, and 6%) and ICU admission (6%, 5%, and 7%) for COVID-19-infected pregnant women were similar across the US, Asia, and Europe, respectively.

• Outcomes: The majority of findings from 42 sources indicates that pregnant women with COVID-19 may be at a higher risk of maternal mortality and maternal and neonatal morbidities than non-pregnant or non-infected women, including: preeclampsia, preterm birth, prelabour rupture of membranes (PROM), caesarean delivery, low birth weight infants, and neonates requiring NICU admission. For example: 
  • A systematic review and meta-analysis (Sept 2020) estimated the rates of caesarean section (72%), premature birth (23%), low birth weight (7%), and adverse pregnancy events (27%) across 61 studies. The rate of caesarean section was substantially higher in Chinese studies (91%) compared to the US (40%) or European (38%) studies. The rates of preterm birth and adverse pregnancy events were also lowest in the US studies (12%, 15%) compared to Chinese (17%, 21%) and European studies (19%, 19%). Adverse pregnancy outcomes were associated with infection acquired at early gestational ages, more symptomatic presentation, myalgia symptom at presentation, and use of oxygen support therapy.
  • A review of systematic reviews (Jan 2021) reported the following rates regarding both preterm and term gestations: 52.3–95.8% for caesarean sections; 4.2–44.7% for vaginal deliveries; 14.3–63.8% for preterm deliveries and 22.7–32.2% for preterm labour; and 5.3–12.7% for PROM and 6.4–16.1% for preterm PROM. Maternal mortality rate was <2%, while stillbirth, NICU admission (which may be attributed to precaution or severe maternal infection), and mortality rates were <2.5%, 3.1–76.9%, and <3%, respectively. Available data were more contradictory for mortality rates, and the increased rates, when reported, have been also attributed to the specific health care provision of the participants’ countries.
  • A systematic review and meta-analysis (Apr 19, 2021) found that SARS-CoV-2 infection in pregnancy, compared with no infection, was associated with preeclampsia, preterm birth, stillbirth, ICU admission, lower birth weight, and NICU admission; COVID-19 was not associated with caesarean delivery, postpartum hemorrhage, or neonatal death compared with no COVID-19. Compared with asymptomatic COVID-19, symptomatic COVID-19 in pregnancy was associated with increased risk of preterm birth and caesarean delivery. Compared with mild COVID-19, severe COVID-19 was strongly associated with preeclampsia, preterm birth, caesarean delivery, low birth weight, and NICU admission.

• Management: Ten studies and four guidelines for the management of pregnant women with COVID-19 generally discussed screening protocols, place of care, staffing models, infection prevention and control measures, delivery timing, medications, and neonatal care. In particular: 
  • These women should be cared for in isolation (ideally negative‐pressure isolation rooms), where there is limited human traffic and appropriate personal protective equipment and infection control measures are followed.  
  • Care should be provided by a multidisciplinary team (e.g., obstetricians, maternal-fetal medicine subspecialists, obstetric anesthetists, midwives).  
  • The timing and mode of delivery should be individualized, dependent mainly on the clinical status of the patient, gestational age, and fetal condition.  
  • Temporary separation of a mother with known/suspected COVID-19 from her newborn should be decided on a case-by-case basis: 1) if temporary separation is chosen, mothers who intend to breastfeed should practice hand and breast hygiene and express their milk, which can be fed to the newborn by a healthy caregiver; or 2) if separation is not chosen, other measures can be used to reduce risk of infection (e.g., face mask use and hand/breast hygiene by mothers before each feeding).  
  • Isolating newborns born to COVID-19 mothers from those born to non-infected mothers may be considered. Newborns born to mothers with confirmed/suspected COVID-19 may be tested 24 hours after birth for SARS-CoV-2 and, if negative, again at approximately 48 hours, if testing capacity is available. 
  • A study (Nov 9, 2020) examined 11 obstetrics guidelines, published from December 2019 to April 2020, from China, Italy, Spain, the UK, and US to compare their recommendations and to assess how useful they could be to maternal health workers. Six guidelines covered more than 80% of the 30 foundational topics the study identified. The study highlighted the existence of 10 points of conflict among the recommendations (i.e., mask wearing, personal and social hygiene, antenatal care visits, partner/companion, antenatal corticosteroids, respiratory analgesia, cord clamping, skin-to-skin practice, mother/child separation, and breastfeeding). The present research revealed a lack of uniformity and consistency, resulting in potentially challenging decisions for health care providers.

• Prone Positioning: Three case reports described successful prone positioning for pregnant patients with COVID-19. For example, a study (Mar 16, 2021) reported that a 31-year-old pregnant woman with symptomatic COVID-19, which was complicated by progressive hypoxemia requiring intensive care and emergent delivery by caesarean section, was successfully supported with mechanical ventilation and prone positioning and ultimately recovered. Prone positioning was implemented in an effort to improve oxygenation.
  • To address the need for low-cost, low-harm interventions during the COVID-19 pandemic wherein hypoxemia predominates, a study (Aug 2020) presented an algorithm for prone positioning of both intubated and non-intubated pregnant women with COVID-19, including indications, contraindications, and a step-by-step guide.

• Medications: Eleven studies were identified on therapeutics for the management of COVID-19-infected pregnant women, including antibiotics, antivirals, glucocorticoids, and immunosuppressants. Recommendations are currently based on limited available data, and more studies are needed to establish evidence-based protocols of care. In particular, data are scarce regarding the efficacy and safety of remdesivir, tocilizumab, and sarilumab in pregnant women with COVID-19; thus, they should be avoided. For example: 
  • A review (Aug 2020) found management of pregnant women with COVID-19 varied according to health institution, with most being treated with medications considered to be relatively safe during pregnancy: antibiotics (e.g., cefoperazone, sulbactam, ceftriaxone, cefazolin, azithromycin), antiviral therapy (e.g., lopinavir, ritonavir, oseltamivir, ganciclovir), and a few were treated with corticosteroids (e.g., dexamethasone, methylprednisolone).
  • A systematic review and meta-analysis (Mar 24, 2021) reported that the proportion of oxygen support, antibiotics, antivirals, and plasma therapy administration, except for hydroxychloroquine, was substantially higher in Asian studies (55%, 78%, 80%, 6%, and 0%) compared to the US (7%, 1%, 12%, 0%, and 7%) or European (33%, 12%, 14%, 1%, and 26%) studies, respectively.⁴ Even in case reports reflecting severe cases, the use of antivirals and antibiotics was higher in Asian studies compared to the US, Latin American, and European studies. The review concluded that minimizing the use of some therapeutics particularly antibiotics, antivirals, oxygen therapy, immunosuppressants, and hydroxychloroquine by risk stratification and careful consideration may further improve maternal and clinical outcomes.
  • A US study (Apr 21, 2021) described the use of remdesivir in hospitalized pregnant women with confirmed COVID-19 infection and O2 saturation <94% who met the criteria to be enrolled in a compassionate use program. Of the 86 patients enrolled in the study, 19 delivered before their first course of remdesivir and were included in the immediate post-partum group. The remaining patients, whose median gestational age was 28 weeks, were started on remdesivir with follow-up after 28 days. After the 28-day follow-up, the oxygen requirement in 96% of the pregnant patients decreased, and 93% of those requiring mechanical ventilation were extubated, 93% recovered, and 90% were discharged. Adverse events (e.g., anemia, constipation, dysphagia, worsening hypoxia) were experienced in 29% (22/67) of the cohort. Other side effects shown included increasing liver function tests and serum creatinine levels with seven pregnant women discontinuing the study drug due to adverse events.

International Scan

• Incidence: The Royal College of Midwives (RCM) and Royal College of Obstetricians and Gynaecologists (RCOG) in the UK notes that pregnant women do not appear more likely to contract COVID-19 than the general population, and the National Institute of Health (NIH) in Italy states that the prevalence of COVID-19 disease in pregnancy appears to be substantially similar to those of the general population. 
• Severity: Guidance and reports from the US (CDC, American College of Obstetricians and Gynecologists [ACOG], NYC Health, and UpToDate), UK (RCM/RCOG), and Italy (NIH) state that there is an increased risk of ICU admission, need for mechanical ventilation and ventilatory support for pregnant women with symptomatic COVID-19 infection, when compared with symptomatic non-pregnant women. Risk factors for severe disease may include age ≥30–35 years, obesity, hypertension, pre-existing diabetes, and immigrant status. 
• Outcomes: Guidance and reports from the US (CDC, ACOG, NYC Health, and UpToDate), UK (RCM/RCOG), and Italy (NIH) indicate that there may be an increased rate of preterm delivery, stillbirth, caesarean delivery, or death in pregnant women with COVID-19 compared to the general pregnant population. It is, however, unclear if these outcomes are directly due to SARS-CoV-2 infection or an indirect effect that results from severe maternal illness or iatrogenic intervention. For example: 
  • A NIH report (Feb 5, 2021) described the results of the Italian Obstetric Surveillance System study, which showed that the average preterm birth rate was 14.4% during the first wave of the pandemic, with a decrease during the observation period. In February and March 2020, the rate was 17.5%; however, the rate fell to 11% in July and August 2020, largely due to increased identification of asymptomatic women at the time of hospitalization. Overall, the majority of preterm births (7.7%) were due to iatrogenic causes, 3.5% to PROM, and 3.2% to spontaneous onset. Moreover, during the first wave of the pandemic, the rate of caesarean section was 33.7% (in line with national rates), and infants who were not separated from their mothers at birth, roomed-in, and received breastmilk had outcomes as good as the infants who were separated from their mothers after birth.
  • A RCM/RCOG report (Feb 19, 2021) noted that, compared to pregnant women without COVID-19, pregnant women with symptomatic COVID-19 requiring hospitalization have overall worse maternal outcomes, including an increased risk of death, although the risk remains very low (the UK maternal mortality rate from COVID-19 is 2.2 per 100,000 maternities). Aside from preterm birth, the report indicated there is no evidence that COVID-19 infection has an adverse effect on the fetus or on neonatal outcomes.
• Management: Guidance and reports from the US (National Institute of Health, CDC, ACOG, Society for Maternal Fetal Medicine [SMFM], UpToDate, and NYC Health), UK (RCM/RCOG), Italy (NIH), Australia (National COVID-19 Clinical Evidence Taskforce), and the World Health Organization (WHO) suggest one or more of the following recommendations for managing pregnant patients with suspected/confirmed COVID-19: appropriate screening, triaging, and isolation; individualized delivery planning; designated multispecialty care teams; and appropriate infection prevention and control measures. In addition, the ACOG has developed an algorithm to evaluate and manage pregnant outpatients with suspected or confirmed SARS-CoV-2 infection.
• Prone Positioning: Guidance and reports from the US (SMFM and UpToDate), Australia (National COVID-19 Clinical Evidence Taskforce), and the WHO suggest prone positioning is feasible in pregnant/postpartum patients with COVID-19 with the help of support devices (e.g., pillows, padding). 
  • The RCM/RCOG report (Feb 19, 2021) from the UK noted that there is little evidence on the use of prone positioning in pregnancy. Guidance from the Intensive Care Society in the UK advises that it is relatively contraindicated in the second and third trimesters of pregnancy, but acknowledges that there is other published guidance available on how this can be undertaken successfully.
• Medications: In the US, the NIH states that potentially effective treatment for COVID-19 should not be withheld from pregnant women because of theoretical concerns related to the safety of therapeutic agents in pregnancy, and the SMFM recommends that remdesivir be offered to pregnant patients with COVID-19 meeting criteria for compassionate use, based on positive results from the Adaptive COVID-19 Treatment Trial (ACTT-1). The UK (RCM/RCOG) and Australia (National COVID-19 Clinical Evidence Taskforce) offered the following recommendations for remdesivir and tocilizumab: 
  • The RCM/RCOG noted that remdesivir should be avoided in pregnant women with COVID-19 unless clinicians believe the benefits of treatment outweigh the risks to the individual. Although data for the use of tocilizumab in pregnancy are limited, there is currently no compelling evidence that tocilizumab is teratogenic or fetotoxic, and so it may be considered in specific cases.
  • The National COVID-19 Clinical Evidence Taskforce recommends considering the use of the following medications for pregnant or breastfeeding women: 1) remdesivir for those hospitalized with moderate to severe COVID-19 who do not require ventilation; and 2) tocilizumab for those who require supplemental oxygen, particularly where there is evidence of systemic inflammation. Sarilumab is not recommended for the treatment of COVID-19 outside of randomized trials with appropriate ethical approval.

• Registries: Registries are being developed to collect data on how COVID-19 affects pregnancy and newborns. For example: 
  • Pregnancy CoRonavIrus Outcomes RegIsTrY (PRIORITY) is the official US registry led by the University of California, San Francisco.  
  • International Registry of Coronavirus Exposure in Pregnancy (IRCEP) is led by an international group of investigators.

Canadian Scan

Incidence: A report (Feb 25, 2021) from the Canadian Surveillance of COVID-19 in Pregnancy (CANCOVID-Preg) examined the epidemiology of 1,880 COVID-19-positive pregnant cases from March 1 to December 31, 2020 across five Canadian provinces (British Columbia, Alberta, Ontario, Quebec, and Manitoba). Although the risk of COVID-19 acquisition among pregnant women cannot be determined from the data, compared to the general population, infection rates appear to be lower among pregnant women in every province with the exception of British Columbia. Among pregnant positive cases, 44.6% were between 30–35 years of age. Most cases were diagnosed between 14–27 weeks’ gestation (38.7%), with infection most often acquired via the community-at-large (50.6%). Obesity was the most common underlying condition (11.9%). The most common symptoms associated with a positive COVID-19 diagnosis during pregnancy were cough (47.0%), headache (31.0%), fever (29.8%) and rhinitis (25.6%).

• Severity: Two Canadian reports suggest that pregnant women with COVID-19 may be at increased risk for hospital or ICU admission compared to non-pregnant women with COVID-19: 
  • The CANCOVID-Preg report (Feb 25, 2021) indicated that although the absolute risk is low, compared to their non-pregnant counterparts, COVID-19-infected pregnant women remain at increased risk of being hospitalized and admitted to the ICU across five Canadian provinces (British Columbia, Alberta, Ontario, Quebec, and Manitoba). Among the 1,839 women with complete information about any COVID-19 related hospitalization or ICU admission from March to December 2020, 8.1% were hospitalized and 1.6% were admitted to the ICU.
  • According to a report (Feb 15, 2021) by the Society of Obstetricians and Gynaecologists of Canada (SOGC), interim Canadian data from a three-province (Ontario, British Columbia, and Alberta) analysis of population outcomes in pregnancy from March 1 to September 20, 2020 reveals that hospitalization and ICU admission are both increased in pregnant women over non-pregnant women by a wider margin. The rate of hospitalization was 11% and the rate of ICU admission was 2.3%.

• Outcomes: Two Canadian reports suggest that pregnant women with COVID-19 may be at risk for some morbidities (e.g., preterm birth): 
  • The CANCOVID-Preg report (Feb 25, 2021) found that among the 738 cases with delivery and gestational age data from March to December 2020, 82.0% occurred at term and 12.3% at preterm gestation across five Canadian provinces (British Columbia, Alberta, Ontario, Quebec, and Manitoba). Preterm birth etiology showed 40.2% were medically indicated and 45.1% were spontaneous. The majority of infants (82.1%) were in the normal range for birth weight (i.e., 2,500–4,000 grams) and were not admitted to the NICU (83.3%).
  • The SOGC report (Feb 15, 2021) noted that the rate of preterm birth was 15% which is approximately twice the background rate in the population across Ontario, British Columbia, and Alberta from March 1 to September 20, 2020. Caesarean section was 33% and neonatal intensive care was 15%.

• Management: Guidance from SOGC, Manitoba, and British Columbia suggest isolating pregnant patients with suspected/confirmed COVID-19 into single-occupancy rooms, minimizing movements between rooms and hospital sites, having designated multidisciplinary care teams, and using droplet and contact precautions. 
• Prone Positioning: A report (Feb 3, 2021) by Alberta Health Services COVID-19 Scientific Advisory Group on prone positioning for awake, non-intubated COVID-19 patients states that if being considered for awake prone positioning outside of a clinical trial, patients should be assessed to determine their risk for escalating care. Low-risk COVID-19 patients, where prone positioning may be implemented with caution on a medical ward, include pregnant women in the second or third trimester.
• Medications: Guidance from SOGC, Manitoba, and British Columbia recommend that certain antibiotics (e.g., amoxicillin, ceftriaxone) and corticosteroids (e.g., dexamethasone) may be administered depending on the patient profile.

Ontario Scan

• Incidence:
  • A report (Apr 26, 2021) by the Better Outcomes Registry & Network (BORN) Ontario reported that the approximate number of currently pregnant individuals in Ontario with a due date after April 1, 2021 is 84,500. There has been a cumulative total of 1,403 laboratory-confirmed positive cases of SARS-CoV-2 infection in pregnant individuals reported between March 1, 2020 and March 31, 2021.

• Severity: 
  • The BORN Ontario report (Apr 26, 2021) found that pregnant individuals in Ontario had higher rates of hospitalization and ICU admission relative to non-pregnant individuals of similar age during the first and second waves of the pandemic.
  • According to SOGC members (Apr 15, 2021), there was a daily wave of pregnant women coming into Ontario ICUs, many requiring ventilators, during April 2021. Pregnant women who have COVID-19 appear more likely to develop respiratory complications requiring intensive care than women and individuals who are not pregnant.

• Outcomes: The BORN Ontario report (Apr 26, 2021) observed a higher rate of preterm birth among infected versus non-infected pregnant individuals in Ontario. Of 1,403 confirmed cases, 792 gave birth at ≥20 weeks of gestational age:  
  • 99.1% of these births were live births;  
  • 11.2% of live births to individuals who had SARS-CoV-2 infection prior to 37 weeks’ gestation were born preterm (for comparison, the incidence of preterm birth in Ontario was 8.3% in 2018/19); 
  • The incidence of stillbirth among these births was 8.8 per 1,000 births (for comparison, the incidence of stillbirth in Ontario was 4.7 per 1,000 births in 2018/19; however, the absolute number of stillbirth events reported in SARS-CoV-2-infected individuals is very low [seven stillbirths] and the incidence should be interpreted cautiously); and  
  • 15.9% of newborns born to mothers with SARS-CoV-2 infection were admitted to a NICU (for comparison, the rate of NICU admission in Ontario was 13.2% in 2018/19).