|Year : 2021 | Volume
| Issue : 1 | Page : 107-112
COVID-19 and pregnancy: Challenges for an anesthesiologist
Shalendra Singh1, Subhasish Patnaik2, Rabi Narayan Hota3, George Cherian Ambooken1, Venigalla Sri Krishna1
1 Department of Anaesthesiology & Critical Care, Armed forces Medical College, Pune, India
2 Department of Anaesthesiology, 05 Airforce Hospital, Jorhat, India
3 Department of Anaesthesiology, 170 Military Hospital, Jammu and Kashmir, India
|Date of Submission||06-Feb-2021|
|Date of Decision||25-Apr-2021|
|Date of Acceptance||27-Apr-2021|
|Date of Web Publication||26-Jun-2021|
Dr. Shalendra Singh
Department of Anaesthesiology and Critical Care, Armed Forces Medical College, Pune - 411 040, Maharashtra
Source of Support: None, Conflict of Interest: None
The anesthetic management of a pregnant patient with coronavirus disease 2019 (COVID-19) presents various unique challenges in terms of patient preparation, intraoperative management, and postoperative concerns, all while taking concurrent measures to prevent the spread of the virus from the patient to the healthcare workers. Anesthetic management of parturient in the era of the COVID-19 pandemic is further complicated by the fact that intubation and extubation are highly aerosol-generating procedures, and are generally advised to be avoided. While various organizations have come up with guidelines on the management of pregnant patients with COVID-19, definitive evidence-based guidelines for the same are lacking. This article aims to consolidate the available literature on the management of pregnant patients with COVID-19, with special impetus on the anesthetic management of these patients.
Keywords: Breastfeeding, cesarean section, COVID-19, neonates, pregnancy
|How to cite this article:|
Singh S, Patnaik S, Hota RN, Ambooken GC, Krishna VS. COVID-19 and pregnancy: Challenges for an anesthesiologist. Arch Med Health Sci 2021;9:107-12
| Introduction|| |
In early December 2019, a cluster of cases of pneumonia caused by a newly identified coronavirus was noted in the Wuhan province of China. This infection has rapidly spread across the world producing a disease that has been termed coronavirus disease 2019 (COVID-19). As the COVID-19 pandemic continues to rage on, it is essential to evaluate the effects of the disease on special populations, including pregnant ladies. Pregnant ladies generally have a high frequency of hospital visits due to their requirement for regular follow-up. Consequently, the number of these patients who are likely to contract COVID-19 is also relatively high.In addition, the altered physiology in a pregnant woman theoretically poses an increased risk of adverse outcomes from contracting the virus. This risk of adverse outcomes in pregnant women makes the perioperative management of a COVID positive parturient undergoing elective as well as emergency obstetric and non-obstetric surgeries a significant challenge.
Currently, the evidence on the management of a pregnant COVID-19 patient is contradictory to an extent and is continually evolving. Based on the available literature, the United States Center for Disease Control and Prevention (CDC) has not categorized pregnant women as a high-risk category. A systematic review of 18 articles including 108 pregnancies reported only three intensive care unit (ICU) admissions and no maternal deaths. However, an Iranian case series later reported maternal deaths in seven out of nine pregnant women with critical COVID-19, raising concerns about the effects of Severe Acute Respiratory Syndrome (SARS) CoV-2 in pregnant women. Despite the contradictory nature of the available literature with certain studies not placing pregnant women to be at an increased risk due to the virus, the mere potential for adverse outcomes necessitates a proper anesthetic management protocol when these patients need to undergo any surgery during the peripartum period. However, only a few case reports elucidate the best plan of anesthesia for pregnant women who are suffering from COVID-19.
In this review article, we have tried to identify the risk of serious complications in parturient, discuss the available literature on vertical transmission of COVID-19 from mother to fetus, the risks to health care providers involved in obstetric management, and anesthetic considerations in both general and neuraxial techniques, and the impact on an already overburdened healthcare service system.
| COVID-19 and Pregnancy|| |
Various viral infections during pregnancy have been shown to cause an increased risk of adverse obstetrical and neonatal outcomes due to the altered physiological and immunological state during pregnancy. The cardiovascular and respiratory components of these changes, along with the development of an immunological adaptation that allows the maternal body to tolerate the antigenically diverse fetus, inflates the risk toward the development of severe respiratory diseases due to influenza. While these complications have been much more recognized with other respiratory viruses, some data also describe serious complications of COVID-19 infection in pregnant women, with adverse maternal and perinatal outcomes such as preterm delivery, ICU admission, and neonatal and intrauterine death being sporadically reported. The categorization of risk from COVID-19 in pregnant patients also varies greatly, with various organizations placing them at differing risk categories. The National Health Services in the United Kingdom has included pregnant women in the list of people at moderate risk of COVID-19 (clinically vulnerable) as a precaution. The Royal College of Obstetrics and Gynecology states in its present guidelines that pregnant women do not appear to be more likely to contract the infection than the general population.
It is therefore evident that the effect of COVID-19 on pregnant patients is incompletely understood. In this scenario where the data on COVID-19 is evolving, researchers have drawn on experiences from previous outbreaks as a guide to infer the severity of COVID-19 in pregnant women. For instance, during the 2009 influenza A virus subtype H1N1 pandemic, infected pregnant women experienced more severe complications compared to the general population, and vaccination was shown to reduce the complications in the neonate. Similarly, the case fatality rates for SARS and the Middle East Respiratory Syndrome (MERS) were significantly higher in pregnant women as compared to non-pregnant women. During the SARS and MERS epidemics, severe sequelae such as preterm deliveries, stillbirths, respiratory complications, and maternal mortality were common. This gave rise to the conjunction that pregnancy would serve to be a significant predictor of severe outcomes in patients with COVID-19, thereby necessitating a detailed examination of the effects of maternal infection on the fetus and childbirth.
| Impact of COVID-19 on a Pregnant Patient|| |
The available data on COVID-19 and pregnancy suggest that neither pregnancy nor delivery increases the chance of acquiring the virus, and there is no evidence of an association with worse clinical outcomes compared with non-pregnant females of the same age group. However, despite the lack of an association in studies conducted till date, there is a growing concern that pregnant mothers are at risk because of physiologic changes occurring during pregnancy. Atelectasis and restriction of the movement of the diaphragm due to the growing fetus, reduced functional residual capacity and increased oxygen consumption are likely to affect pulmonary reserve and can result in adverse patient outcomes. In addition, some studies have reported that pregnant women who developed COVID-19-associated pneumonia have an increased risk for obstetric complications (e.g., preterm labor, premature rupture of membranes, preeclampsia, and increased risk for cesarean section (CS). It has been suggested that triaging of pregnant patients with COVID-19 could aid in their management. Based on clinical evaluation, Liang and Acharya classified a symptomatic patient with stable vital signs as a mild case of COVID-19. Pregnant patients with tachypnea and hypoxemia expressed as a ratio of the partial pressure of arterial blood oxygen/oxygen concentration in inspired gas (PaO2/FiO2), with a value ≤300 mm Hg are classified as severe cases. Patients presenting with shock and multiorgan system failure requiring mechanical ventilation are classified as critical cases. This identification of severe cases would also help identify the risk of adverse obstetric outcomes, as these are associated with each other.
| Effect of COVID-19 on Fetal Outcome|| |
Intrauterine transmission is a reasonable concern; however, current evidence suggests that vertical transmission is unlikely., Although COVID-19 has not been detected in umbilical cord blood and evidence supporting vertical transmission is not available, three cases have been reported in which neonates have developed pneumonia despite strict infection control measures being implemented. It has been hypothesized that vertical transmission of COVID-19 is possible across the maternal-fetal interface, by utilization of angiotensin-converting enzyme 2 receptors. However, this hypothesis is yet to be proven. In addition, it is noteworthy that the increase in the body temperature associated with COVID-19 has been postulated to cause congenital anomalies if it occurs in the first trimester.
Apart from the vertical transmission of disease to the newborn, horizontal transmission to neonates also proved to be a concern. Airborne droplets can spread the COVID-19 to inpatient neonates if measures of social distancing are not implemented by the mothers with caregivers, visitors, or healthcare personnel. As a combined method for prevention of vertical and horizontal disease transmission, early umbilical cord clamping during delivery is recommended and symptomatic mothers as mentioned above should maintain the mandated six feet distance from their neonate until recovery in order to reduce the risk of viral transmission from the mother to the child. The mother is considered as recovered on elapse of two weeks without any symptoms or two sequential reverse transcriptase-polymerase chain reactions tests being negative.
| Breastfeeding|| |
Antiviral drug transmission through breastfeeding is confirmed in rats, but not in humans and hence antivirals are considered safe. The International Federation Gynecology and Obstetrics, has stated that despite limited research on the topic having presently being conducted, the available evidence has failed to demonstrate virus isolation in breast milk. In addition, any suspension of breastfeeding will require regular emptying of breasts to avoid breast engorgement and subsequent infection, and it would also serve to be a challenge to maintain adequate lactation till it becomes safe for the mother to directly breastfeed the baby. Breastfeeding should only be allowed following maternal recovery, with continued emphasis on frequent hand washing and breast hygiene. Therefore, the current evidence suggests that the benefits of breastfeeding seem to outweigh any potential risks of transmission of the virus through breast milk.
| Role of Corticosteroids and Thromboprophylaxis|| |
Due to their role in aiding fetal lung maturation, corticosteroids have an integral part in the management of pregnancies that are at a high risk of preterm labor. A few studies have however shown a worse prognosis for pregnant ladies with viral infections who receive corticosteroids. Therefore, there is a need to balance the guidelines regarding the use of corticosteroids in pregnant patients with COVID-19; keeping in mind the potential benefits for the fetus vis-à -vis the deleterious effects for the mother. A recent article has recommended that no patient suspected of having COVID-19 should receive corticosteroids after 32 weeks of gestation. In addition, recommendations also state that a materno-fetal medicine consult may be taken for decisions regarding the administration of corticosteroids in pregnancies <32 weeks, with the decision being guided by the risk-benefit ratio of administration of the drugs. Further robust guidelines would aid in the management of COVID-19 patients who are at high risk of preterm delivery.
Another area of concern in pregnant patients with COVID-19 is that both pregnancy and COVID-19 are prothrombotic states. While various organizations have released guidelines on the use of thromboprophylaxis in patients with concurrent pregnancy and COVID-19, they vary to a great extent from each other. A recent review article also suggested that there is no additional benefit of including routine thromboprophylaxis with low-molecular-weight heparin in pregnant patients with COVID-19 and that it might increase the risk of bleeding without any reduction in the thrombotic risk.
| Obstetric Anaesthesia and COVID-19|| |
The perioperative anesthetic management of a patient with suspected or confirmed COVID-19 infection presents a major challenge for anesthesia professionals because of the poorly understood pathophysiology, and confirmed rapid human-to-human transmission of the virus through carriers. Similar to SARS and MERS, the primary goal in the operating room (OR) is to prevent cross-contamination by implementing strict anesthesia guidelines and infection control strategies during the perioperative period. The American Association of Nurse Anaesthetists has published an infographic highlighting anesthetic considerations in managing patients with COVID-19 infection. The limited knowledge and clinical experience about the impact and management of COVID-19 parturient pose a potential anesthetic challenge during labor as well as operative deliveries. Professional societies have issued interim guidance regarding the evaluation and management of pregnant women with COVID-19.,,,,,, The anesthetic management of the COVID-19 parturient can be divided into three distinct headings which have been mentioned below.
Before hospital admission, a telephonic consult may be conducted for screening of symptoms and contact history. If the patient does not report symptoms suggestive of COVID-19, then routine perinatal care may be conducted with adequate measures to prevent exposure. However, a severity assessment is to be performed if the patient presents to the clinic with symptoms. Preoperatively, any patient showing symptoms should be isolated, preferably in a negative pressure room. It is also recommended that all healthcare providers involved in care should wear gowns, gloves, N95 masks, and face shields (as per hospital protocol). The patient should also wear a surgical mask. The hospital adopted checklists may be used for donning and doffing of appropriate personal protective equipment (PPE). If possible, an observer should be appointed for the same.
In addition, preparation during the preoperative phase is of utmost importance while managing COVID-19 patients, as these measures have the greatest potential for the prevention of horizontal transmission of the disease. For example, it is recommended that routine laboratory studies may be conducted for all patients so that neuraxial anesthesia may be provided to all patients who do not have thrombocytopenia. A further recommendation is to pre-prepare a COVID-19 OR kit (including uterotonic agents, vasopressors, narcotics for intrathecal administration, and antiemetics) in advance, to avoid contaminating the medication station. A dedicated OR is necessary for patients with confirmed or suspected COVID-19 to avoid cross-contamination between cases. It is also important to have a system in place to alert the necessary staff for backup coverage and to assign a runner outside the OR to retrieve supplies or to help if needed. For COVID-19 testing, prioritize patients with suspected COVID-19 or those who have signs and symptoms suggestive of COVID-19.
As per available literature, there is no contraindication for the use of spinal anesthesia in patients with COVID-19. However, all standard precautions should be followed while performing the procedure and the use of excessive or deep sedation is to be avoided. In order to minimize the viral spread, the patient should wear a surgical mask at all times. The decision to use a particular anesthetic technique for cesarean delivery is based on a variety of factors, including risks to the parturient or fetus and the skill set of the provider. The use of neuraxial blockade techniques is advised during delivery of COVID-19 patients, whether by vaginal route or CS because these techniques are known to decrease the cardiopulmonary compromise caused by the stress of labor. As far as possible, sedative drugs should be avoided due to their respiratory depressive effects. If supplemental oxygen is needed, it should be given at the lowest flow possible. However, even though there is no evidence to suggest that COVID-19 might spread to the cerebrospinal fluid (CSF), contact with the patient's CSF should be avoided as much as possible while performing any neuraxial procedure. Epidural blood patch and sphenopalatine block are advised to be used only in case the patient develops a postdural puncture headache which cannot be managed by systemic analgesics.
The use of general anesthesia is to be discouraged since it is a highly aerosol-generating procedure. However, if general anesthesia is indicated, all personnel in the OR at the time of intubation should wear the requisite PPE. In addition, minimal essential staff is to be stationed inside the OR during intubation. Preoxygenation should occur with a breathing circuit extension with a high-quality viral filter at the patient end of the circuit. In addition, it is important to maximize the chance of first-pass intubation by providing adequate muscle relaxation, and by having an experienced anesthesiologist manage the airway. If available, the use of video laryngoscopy is recommended to reduce the number of attempts at intubation. Extubation also has a high risk of aerosolization of the virus. Consequently, minimal numbers of personnel are to be present inside the OR during extubation and all personnel present inside the OR are to don full complement PPE. The patient should be monitored in the OR until recovery before transferring to a COVID-19–designated postoperative room as per hospital guidelines.
The advantage of regional anesthetic techniques over general anesthesia is that it is not associated with aerosol generation. During tracheal intubation, the risk of transmission of upper respiratory tract infection to healthcare providers is known to be 6.6 times greater than those not exposed to intubation. Regional anesthesia offers the benefit of avoiding airway manipulation and instrumentation; this decreases the chance of coughing and viral aerosolization associated with intubation and extubation., Apart from the benefits of reducing aerosolization, neuraxial anesthesia also has various other established advantages in patients undergoing CS. It is well established that regional anesthesia helps in the reduction of pain scores, opioid consumption, postoperative nausea and vomiting, and the risk of aspiration and difficult airway associated with general anesthesia. In addition, spinal anesthesia has advantages over general anesthesia for CS because it has lower rates of respiratory depression and it is not deliberated as an aerosolizing procedure, so theoretically, it will decrease the need for PPE (i.e., decrease the chance of spread of the virus to health workers in the OR). Besides, the maintenance of pulmonary function may reduce postoperative complications in a patient with confirmed COVID-19 infection and associated pneumonia or acute respiratory distress syndrome.
During the postoperative management of pain, data against the use of nonsteroidal anti-inflammatory drugs lack sufficient evidence. Antiemetics are to be administered in order to prevent vomiting in patients undergoing cesarean delivery, as gagging and vomiting are considered aerosolization events. The use of dexamethasone in this patient population is considered ideal for postoperative nausea and vomiting prophylaxis and treatment. Healthcare facilities providing inpatient obstetric care should limit visitors only to those essential for the patient's postnatal care. The use of communication techniques that avoid person-to-person contacts, such as phone calls and videoconferences are to be encouraged.
| Complications|| |
A few case reports have shown serious complications of COVID-19 infection associated with pregnancy. Mullins et al.analyzed 23 case reports and case series and reported adverse outcomes including ICU admissions. In the same narrative review, 47% of pregnant women admitted to the hospital had preterm delivery. Similar findings were described in a systematic review and meta-analysis of 19 studies showing that 41% of the pregnant women infected with COVID-19 delivered prematurely at <37 weeks.
Caesarean versus normal delivery
There is variability in the rate of cesarean delivery in COVID-19–infected patients as compared to the general population. An analysis of 108 pregnancies showed that a majority of pregnant women with COVID-19 underwent cesarean delivery. Furthermore, most women undergoing cesarean delivery had thrombocytopenia and elevated C-reactive protein, which is likely to increase the severity of COVID-19 and neurologic complications. In addition, there have also been reports of maternal deaths in patients with COVID-19 due to respiratory complications after delivery.
Even though a generally poor outcome has not been well recognized to date, neonatal and intrauterine deaths have been reported in reviews of numerous studies.
Other critical illnesses
Information from a small number of case reports or series indicates that the clinical findings of pregnant women with COVID-19 are similar to those in non-pregnant women. In addition, the severity of the disease in pregnant women is similar to that in other adults. However, reviews of COVID-19 cases in pregnant women have reported severe and critical illness requiring hospitalization and ICU admission.
| Conclusion|| |
As the COVID pandemic rages on, with the number of cases of COVID-19 steadily increasing, the number of challenging obstetric cases with COVID-19 is also likely to increase. Thankfully though, there is no evidence presented to suggest an increased risk for pregnant women from the virus. Obstetric anesthesia remains a significant challenge in the pandemic era, and operative deliveries are associated with more spread of the virus. Despite there being is a high risk of contamination involved with CS, neuraxial techniques are considered safe and also not associated with any aerosol generation. Breastfeeding is considered safe provided adequate measures are taken to prevent droplet transmission.
A multidisciplinary approach and a comprehensive preanaesthesia preparation can improve the safety of mothers and infants and reduce the risk of transmission of infection to the hospital staff, and would be conducive to epidemic prevention and control. Every health care institution across the world has been working diligently to educate its employees on the current recommendations that comply with the CDC and other national organizations. Educating healthcare workers regarding the correct usage of PPE and standardized protocols can help us to deal with this prevailing epidemic and practice safe obstetric anesthesia.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Zhu N, Zhang D, Wang W. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med 2020;382:727-33.
Zaigham M, Andersson O. Maternal and perinatal outcomes with COVID-19: A systematic review of 108 pregnancies. Acta Obstet Gynecol Scand 2020;99:823-9.
Hantoushzadeh S, Shamshirsaz AA, Aleyasin A, Seferovic MD, Aski SK, Arian SE, et al
. Maternal death due to COVID-19. Am J Obstet Gynecol 2020;223:109.e1-109.e16.
Singh S, Sethi N. Neuroanesthesia and pregnancy: Uncharted waters. Med J Armed Forces India 2019;75:125-9.
Liu H, Wang LL, Zhao SJ, Kwak-Kim J, Mor G, Liao AH. Why are pregnant women susceptible to COVID-19? An immunological viewpoint. J Reprod Immunol 2020;139:103122.
Creanga AA, Johnson TF, Graitcer SB, Hartman LK, Al-Samarrai T, Schwarz AG, et al
. Severity of 2009 pandemic influenza A (H1N1) virus infection in pregnant women. Obstet Gynecol 2010;115:717-26.
Di Mascio D, Khalil A, Saccone G, Rizzo G, Buca D, Liberati M, et al
. Outcome of coronavirus spectrum infections (SARS, MERS, COVID-19) during pregnancy: a systematic review and meta-analysis. Am J Obstet Gynecol MFM 2020;2:100107.
Elsaddig M, Khalil A. Effects of the COVID pandemic on pregnancy outcomes [published online ahead of print, 2021 Mar 18]. Best Pract Res Clin Obstet Gynaecol. 2021;(S1521-693421)00043-2.
Rothe C, Schunk M, Sothmann P, Bretzel G, Froeschl G, Wallrauch C, et al
. Transmission of 2019-nCoV infection from an asymptomatic contact in Germany. N Engl J Med 2020;382:970-1.
Tan EK, Tan EL. Alterations in physiology and anatomy during pregnancy. Best Pract Res Clin Obstet Gynaecol 2013;27:791-802.
Masmejan S, Pomar L, Lepigeon K, Favre G, Baud D, Rieder W. COVID-19 et grossesse [COVID-19 and pregnancy]. Rev Med Suisse 2020;16:944-6.
Liang H, Acharya G. Novel corona virus disease (COVID-19) in pregnancy: What clinical recommendations to follow? Acta Obstet Gynecol Scand 2020;99:439-42.
Chen L, Li Q, Zheng D, Jiang H, Wei Y, Zou L, et al
. Clinical characteristics of pregnant women with COVID-19 in Wuhan, China. N Engl J Med 2020;382:e100.
Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, et al
. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: A descriptive study. Lancet 2020;395:507-13.
Chen H, Guo J, Wang C, Luo F, Yu X, Zhang W, et al
. Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: A retrospective review of medical records. Lancet 2020;395:809-15.
Schwartz DA. An analysis of 38 pregnant women with COVID-19, their new-born infants, and maternal-fetal transmission of SARS-CoV-2: Maternal coronavirus infections and pregnancy outcomes. Arch Pathol Lab Med 2020;144:709-805.
Tripathi S, Gogia A, Kakar A. COVID-19 in pregnancy: A review. J Family Med Prim Care 2020;9:4536-40. [Full text]
Khan MS, Nabeka H, Akbar SMF, Al Mahtab M, Shimokawa T, Islam F, et al
. Risk of congenital birth defects during COVID-19 pandemic: Draw attention to the physicians and policymakers. J Glob Health 2020;10:020378.
Della Gatta AN, Rizzo R, Pilu G, Simonazzi G. Coronavirus disease 2019 during pregnancy: A systematic review of reported cases. Am J Obstet Gynecol 2020;223:36-41.
Poon LC, Yang H, Kapur A, Melamed N, Dao B, Divakar H, et al
. Global interim guidance on coronavirus disease 2019 (COVID-19) during pregnancy and puerperium from FIGO and allied partners: Information for healthcare professionals. Int J Gynaecol Obstet 2020;149:273-86.
Elshafeey F, Magdi R, Hindi N, Elshebiny M, Farrag N, Mahdy S, et al
. A systematic scoping review of COVID-19 during pregnancy and childbirth. Int J Gynaecol Obstet 2020;150:47-52.
London V, McLaren R Jr., Atallah F, Cepeda C, McCalla S, Fisher N, et al
. The relationship between status at presentation and outcomes among pregnant women with COVID-19. Am J Perinatol 2020;37:991-4.
D'Souza R, Malhamé I, Teshler L, Acharya G, Hunt BJ, McLintock C. A critical review of the pathophysiology of thrombotic complications and clinical practice recommendations for thromboprophylaxis in pregnant patients with COVID-19. Acta Obstet Gynecol Scand 2020;99:1110-20.
Society for Maternal Fetal Medicine. COVID Clinical: Publications and Clinical Guidance. Available from: https://www.smfm.org/covidclinical
. [Last accessed on 2020 Apr 24; Last updated on 2020 May 26]
Rollins M, Lucero J. Overview of anesthetic considerations for cesarean delivery. Br Med Bull 2012;101:105-25.
Tran K, Cimon K, Severn M, Pessoa-Silva CL, Conly J. Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: A systematic review. PLoS One 2012;7:e35797.
Ashokka B, Chakraborty A, Subramanian BJ, Karmakar MK, Chan V. Reconfiguring the scope and practice of regional anesthesia in a pandemic: The COVID-19 perspective. Reg Anesth Pain Med 2020;45:536-43.
Lie SA, Wong SW, Wong LT, Wong TGL, Chong SY. Practical considerations for performing regional anesthesia: Lessons learned from the COVID-19 pandemic. Can J Anaesth 2020;67:885-92.
Narang K, Enninga EA, Gunaratne MD, Ibirogba ER, Trad AT, Elrefaei A, et al
. SARS-CoV-2 infection and COVID-19 during pregnancy: A multidisciplinary review. Mayo Clin Proc 2020;95:1750-65.
Mullins E, Evans D, Viner RM, O'Brien P, Morris E. Coronavirus in pregnancy and delivery: Rapid review. Ultrasound Obstet Gynecol 2020;55:586-92.
Karimi-Zarchi M, Neamatzadeh H, Dastgheib SA, Abbasi H, Mirjalili SR, Behforouz A, et al
. Vertical transmission of coronavirus disease 19 (COVID-19) from infected pregnant mothers to neonates: A review. Fetal Pediatr Pathol 2020;39:246-50.
Gajbhiye R, Modi D, Mahale S. Pregnancy outcomes, Newborn complications and Maternal-Fetal Transmission of SARS-CoV-2 in women with COVID-19: A systematic review of 441 cases. medRxiv [Preprint]. 2020.