The current coronavirus disease 2019 (COVID-19) pneumonia pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading globally at an accelerated rate, with a basic reproduction number (R0) of 2e2.5, indicating that 2e3 persons will be infected from an index patient. A serious public health emergency, it is particularly deadly in vulnerable populations and communities in which healthcare providers are insufficiently prepared to manage the infection. As of March 16, 2020, there are more than 180,000 confirmed cases of COVID-19 worldwide, with more than 7000 related deaths. The SARS-CoV-2 virus has been isolated from asymptomatic individuals, and affected patients continue to be infectious 2 weeks after cessation of symptoms. The substantial morbidity and socioeconomic impact have necessitated drastic measures across all continents, including nationwide lockdowns and border closures.Pregnant women and their fetuses represent a high-risk population during infectious disease outbreaks. To date, the outcomes of 55 pregnant women infected with COVID-19 and 46 neonates have been reported in the literature, with no definite evidence of vertical transmission. Physiological and mechanical changes in pregnancy increase susceptibility to infections in general, particularly when the cardiorespiratory system is affected, and encourage rapid progression to respiratory failure in the gravida. Furthermore, the pregnancy bias toward T-helper 2 (Th2) system dominance, which protects the fetus, leaves the mother vulnerable to viral infections, which are more effectively contained by the Th1 system. These unique challenges mandate an integrated approach to pregnancies affected by SARS-CoV-2.Here we present a review of COVID-19 in pregnancy, bringing together the various factors integral to the understanding of pathophysiology and susceptibility, diagnostic challenges with real-time reverse transcription polymerase chain reaction (RT-PCR) assays, therapeutic controversies, intrauterine transmission, and maternalÀfetal complications. We discuss the latest options in antiviral therapy and vaccine development, including the novel use of chloroquine in the management of COVID-19. Fetal surveillance, in view of the predisposition to growth restriction and special considerations during labor and delivery, is addressed. In addition, we focus on keeping frontline obstetric care providers safe while continuing to provide essential services. Our clinical service model is built around the principles of workplace segregation, responsible social distancing, containment of cross-infection to healthcare providers, judicious use of personal protective equipment, and telemedicine. Our aim is to share a framework that can be adopted by tertiary maternity units managing pregnant women in the flux of a pandemic while maintaining the safety of the patient and healthcare provider at its core.

What is already known about this topic? COVID-19 infection in pregnancy leads to an increase in adverse maternal outcomes. Owing to paucity of data regarding SARS-CoV-2 vaccine use in pregnancy there is uncertainty regarding safety of use and subsequent pregnancy outcomes. What does this study add? Provides an overview of the available SARS-CoV-2 vaccines, their mechanisms of action and feasibility of use in pregnancy. Summarises recommendations regarding vaccination of pregnant or lactating women. Data Availability-Data sharing is not applicable to this article as no new data were created or analyzed in this study. Acknowledgements:We would like to acknowledge Mr Mohesh K Mohan for his assistance in the illustration, Ms Cecille Laureano Asibal for her administrative support.

We thank Carbillon and coworkers for their perspectives on the optimal dose of chloroquine in pregnancy. The novel use of chloroquine phosphate and hydroxychloroquine in the management of coronavirus disease 2019 (COVID-19) is an area of evolving research. Our rationale for high-dose chloroquine was based, at the time, on expert consensus from the Chinese Ministry of Health and data from the interim analysis of a study by the Health Commission of Guangdong province, China, which supported the use of a twice-daily 500-mg regimen in the clinical management of COVID-19. 1 However, important findings from a subsequent doublemasked, randomized phase IIb clinical trial from Brazil (ClinicalTrials.gov number, NCT 04323527) of adults with severe COVID-19 have since demonstrated that high-dose chloroquine is associated with greater toxicity and mortality from QTc prolongation. 2 Although these results are not generalizable across the COVID-19 disease spectrum, we now caution against the use of high-dose regimens and advise providers to consult their institutional protocols when considering these drugs as a treatment option in pregnancy. Rancourt and colleagues astutely highlight the influence of body mass index (BMI) on disease outcomes. Although anthropometric data of pregnant women with COVID-19 were not available during the initial stages of the pandemic, obesity is now a well-recognized risk factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. 3 Cohort studies of nonpregnant adults with COVID-19 and a BMI >35 kg/m 2 have demonstrated a higher risk for admission to critical care and the need for invasive mechanical ventilation. Similar trends are observed in pregnancy; our recent systematic review of 637 pregnant women with laboratory-confirmed SARS-CoV-2 infection demonstrated a 40% prevalence of obesity and diabetes mellitus among COVID-19erelated maternal mortalities reported between December 2019 and May 2020. 4 Prospective data from the United Kingdom Obstetric Surveillance System in addition reveal that overweight and obese pregnant women with COVID-19 were at least twice as likely to require admission to hospital when compared with those with a BMI <25 kg/m 2. 5 It is believed that obesity attenuates cardiorespiratory reserves and amplifies circulating serum interleukin-6 levels; the latter, by instigating a cytokine storm, results in a significantly elevated risk of severe disease and mortality from COVID-19. 3,4 Pregnant women who are obese and battling COVID-19 would therefore find themselves between Scylla and Charybdis, where gravid physiology and disease pathology collide to encourage progression to critical illness.

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