Literature DB >> 33305352

COVID-19 infection in pregnant women: Review of maternal and fetal outcomes.

Deemah Salem1,2, Fawzi Katranji3, Talah Bakdash4.   

Abstract

Pregnant women, their fetuses, and newborns are likely to represent a high-risk population during the current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Literature on the outcomes of COVID-19 infections during pregnancy is slowly building up. The aim of the present review was to gather evidence from relevant articles published in English from January to August 2020 in Medline and Google Scholar. The review revealed that pregnant women who become COVID-19-positive are usually either asymptomatic or mild-to-moderately symptomatic, similar to non-pregnant women. Pneumonia is one of the most common outcomes in pregnant women with COVID-19. However, it cannot be conclusively said that SARS-CoV-2 infection increases the risk of maternal, fetal, and neonatal complications. Pregnant women with COVID-19 with co-morbidities have increased risks of complications: there are regional variations in the rates of adverse outcomes reported. Though uncommon, the review shows that vertical transmission is possible. Additionally, the third trimester seems to be the most vulnerable period of infection. This aspect needs to be researched further to activate surveillance programs at the end of second trimester. Overall, it is necessary to monitor pregnant women before and after delivery, and their infants, during this pandemic.
© 2020 International Federation of Gynecology and Obstetrics.

Entities:  

Keywords:  COVID-19; SARS-CoV-2; adverse effects; fetal outcome; hospital admission; maternal outcome; pregnant women; vertical transmission

Mesh:

Year:  2020        PMID: 33305352      PMCID: PMC9087662          DOI: 10.1002/ijgo.13533

Source DB:  PubMed          Journal:  Int J Gynaecol Obstet        ISSN: 0020-7292            Impact factor:   4.447


INTRODUCTION

In December 2019, a viral outbreak emerged from Wuhan in the Hubei province of China, reportedly being caused by a novel coronavirus. It has now spread worldwide and is one of the most severe public health threats. The virus was named severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and the disease was called coronavirus disease 2019 (COVID‐19). On March 11, 2020, WHO announced COVID‐19 as a “pandemic”. Previously, a total of six coronavirus species belonging to the genus Alphacoronavirus (HCoV‐229E and HCoV‐ NL63) and Betacoronavirus (HCoV‐OC43, HCoV‐HKU1, severe acute respiratory syndrome CoV [SARS‐CoV], and Middle East respiratory syndrome [MERS‐CoV]) were known to infect humans. With the emergence of SARS‐Cov‐2, there are now seven species of coronavirus infecting humans. The physiologic and immunologic changes during pregnancy may result in systemic effects that predispose women towards complications from respiratory infections leading to maternal and fetal mortality and morbidity. , Both SARS‐CoV and MERS‐CoV were known to be associated with adverse outcomes in pregnant women with greater mortality rates than the general population. , With SARS‐CoV‐2 rapidly spreading, it is reasonable to contemplate that pregnant women are likely to get infected. Worldwide concerns have been raised about the risk of intrauterine transmission of this virus from the mother to the fetus. , The clinical characteristics and possibility of transmission of COVID‐19 in pregnant women vertically or during delivery are still unclear. , , The questions that require immediate attention include the following: whether the symptoms of the disease in pregnant women with COVID‐19 differ from symptoms in non‐pregnant women; whether complications of the disease and mortality rate are higher in pregnant women than in non‐pregnant women; and whether there is a chance of premature delivery or fetal mortality, or even vertical transmission of the disease. , Finding answers to these questions are crucial for planning effective obstetrical management for pregnant women with COVID‐19. Given the importance of the issue, the present narrative review collates the literature assessing the effect of COVID‐19 infection in pregnancy, including the maternal and fetal outcomes of COVID‐19, vertical transmission, as well as the benefits of screening for COVID‐19 in pregnant women.

MATERIALS AND METHODS

A detailed literature search was carried out using databases such as Medline and Google Scholar. The following search terms were combined using Boolean operators “AND/OR”: “COVID‐19”; “SARS‐CoV‐2”; “Maternal effect”; “Maternal outcome”; “Fetal effect”; “Fetal outcome”; “Vertical transmission”; “Pregnancy outcome”; “Antenatal”; “Perinatal”; and “Screening.” Relevant literature reporting both maternal and fetal outcomes of COVID‐19 during pregnancy and published in English from January 1, 2020, to August 31, 2020, was retrieved. The retrieved literature was filtered to include only systematic reviews, meta‐analyses, clinical trials, retrospective real‐world studies, case series, and narrative reviews. No randomized trials were retrieved. Publications covering only maternal or fetal outcomes and those for which full text was not available were not included. In addition, publications covering the treatment and/or management of COVID‐19 and/or its outcomes in pregnancy were not included in the narrative review. Of the remaining publications, the authors have tried to present a mix of different types of publications reporting unique data.

TRANSMISSION OF SARS‐COV‐2

The principal transmission routes for SARS‐CoV‐2 include droplets and aerosols, mainly through inhalation of respiratory droplets produced by coughing or sneezing by infected persons. Moreover, transmission also occurs via hand to mouth/nose route from infected droplets deposited on different surfaces and objects. , The virus transmission could potentially occur in individuals at a distance of 1 meter from the infected person.

PREGNANCY AND SUSCEPTIBILITY TOWARDS SARS‐COV‐2 INFECTION COMPARED TO NON‐PREGNANT WOMEN

Pregnancy causes physiological changes in the respiratory and circulatory systems as well as alterations in immunological reactions. These are the primary factors that are likely to make pregnant women more vulnerable to viral infections. The common changes in the respiratory system that are likely to increase the susceptibility of a pregnant woman to respiratory infections include reduced functional residual volumes, elevation of the diaphragm, relaxation of ligaments in the ribs, increased pulmonary hypertension resulting in hyperventilation, and even hypoxic respiratory failure. , Altered cell immunity increases pregnant women's risk of an immunocompromised state, thereby making them more prone to develop worst outcomes. , Moreover, viral infection in pregnancy can result in modification of the cardiovascular system, increased metabolic rate and consumption of oxygen, higher pulmonary vascular resistance, and even heart failure. Additionally, during the third trimester of pregnancy, the probability of physical dyspnea is high (due to increased maternal oxygen demands, gestational anemia, and consumption of fetal oxygen) leading to further worsening of breathing difficulties. It is important to note that pregnant women are susceptible to SARS‐CoV‐2 infection. However, despite there being many respiratory, circulatory, and immunological factors that could increase a pregnant woman's risk of SARS‐CoV‐2 infection, the data available so far do not reflect an increased risk. In their literature review, Selim et al. report very small absolute risks of SARS‐CoV‐2 infection in pregnancy. Also, there is no evidence to date that pregnant women are more susceptible to SARS‐CoV‐2 infection than non‐pregnant women. In general, the unique immunologic changes of pregnancy are thought to suppress the virulence of the virus. The symptoms of COVID‐19 in pregnant women are thought to be due to the direct effect of the virus on the mothers. The disease course of SARS‐CoV‐2 in pregnant women seems to be either asymptomatic or with mild to moderate symptoms (fever and cough), similar to non‐pregnant women. , , In pregnant women presenting with severe symptoms (e.g. hypoxia, pneumonia, etc.), enhanced angiotensin‐converting enzyme 2 (ACE‐2) expression is thought to be linked to severity of symptoms. A recent meta‐analysis reported that less than 20% of pregnant women need admission to the intensive care unit (ICU). In a Chinese study on hospitalized pregnant women with COVID‐19, 77% had fever and 23% reported dyspnea. Of these cases, 23% improved with treatment and discharged with ongoing pregnancy, while 46% had preterm labor at 32–36 weeks of pregnancy. Only 7.6% developed severe pneumonia and even multi‐organ dysfunction, requiring ICU care and extracorporeal membrane oxygenation. The rate of critical care in pregnant women with COVID‐19 was similar to that reported in the general population (7.6% vs 5%). Chen et al. reported epidemiological, clinical, and laboratory characteristics and outcomes of 118 pregnant women with confirmed SARS‐CoV‐2 infection in China. Among them, 92% had mild disease and 8% had severe disease with hypoxemia. The condition of one patient was critical, requiring non‐invasive mechanical ventilation, which was continued even after delivery. Six women developed severe disease after delivery; 94% were discharged without any complications and no death was reported. The risk of severe disease among pregnant women was comparable with the risk reported in the general population suffering from COVID‐19 across mainland China.

PREGNANCY OUTCOMES IN COVID‐19

COVID‐19 infection is very new. Data on clinical outcomes of pregnant women suffering from COVID‐19 are therefore relatively scarce. Selim et al. report that SARS infection (but not SARS‐CoV‐2 infection) has been associated with a higher risk for intrauterine growth retardation, premature births, and spontaneous abortion. This is also reflected in a publication that shows that compared to maternal outcomes in SARS‐CoV and MERS‐CoV infections, the maternal outcomes in SARS‐CoV‐2 are more favorable, with lower morbidity and mortality, with case fatality rates of 18%, 25%, and 0%, respectively. However, recently a meta‐analysis of 13 publications (n = 114) reported preterm births, neonatal pneumonia, and respiratory distress syndrome in infants born of COVID‐19‐positive mothers. There are also regional variations in the rate of maternal and neonatal complications. A meta‐analysis by Dubey et al. reported that the rates of cesarean deliveries and adverse pregnancy outcomes were substantially higher in Chinese studies (91% and 21%) compared to American (40% and 15%) and European studies (38% and 19%). Similarly, the rates of preterm births were lower in American studies (12%) compared to Chinese and European studies (17% and 19%, respectively). Therefore, since the infection is new, care should be taken to monitor COVID‐19‐positive pregnant women to prevent adverse maternal and fetal outcomes. The reported maternal and fetal outcomes in pregnant women infected with COVID‐19 are outlined in Table 1.
TABLE 1

Pregnancy outcomes in women with COVID‐19 seen in various studies

Author and year Country Study design Study population with COVID−19 infection (n) Maternal effects Fetal effects
Capobianco et al., 20 July 2020ChinaSystematic review and meta‐analysis13 publications (n = 114) (retrospective studies, cohort study, case series, and case reports)

Most commonly reported symptoms: fever and cough

Maternal complications pooled prevalence: 45.0% (95% CI 24.0 –67.0)

Admission to ICU: <20%

Preterm infants pooled proportion: 23.0% (95% CI 11.0–39.0)

Most frequent neonatal complications: pneumonia and respiratory distress syndrome

Infected infants pooled proportion: 6.0% (95% CI 2.0–12.0)

Dubey et al., 23 July 2020GlobalSystematic review and meta‐analysis61 publications (790 COVID−19‐positive women and 548 infants)

Most common presentations: fever, cough, and dyspnea (not requiring mechanical ventilation)

Lymphopenia: 46%

Elevated CRP: 48%

Cesarean delivery: 72%

Adverse pregnancy outcomes (preterm births and death/stillbirth or early terminated pregnancies): 27%

Low birth weight: 7%

Neonatal COVID‐19 infection: 1%

Elshafeey et al., 28 April 2020GlobalSystematic review33 publications (385 COVID−19 positive pregnant women and 256 infants)

Mild symptoms (95.6%), severe (3.6%), critical (0.8%)

Mechanically ventilated: 1.5%

Maternal mortality: 0.3%

Cesarean delivery: 69.4%

RT‐PCR positive: 1.6%

Neonatal death: 0.4%

Zaigham and Andersson, 29 April 2020GlobalSystematic review of case series and case reports18 publications (n = 108)

Most presented at third trimester: 68%

Most presenting symptoms: fever and cough

Lymphocytopenia: 59%

Elevated CRP: 70%

Cesarean delivery: 91%

Admission to ICU: 3 patients

Intrauterine death: 1

IUGR: 1

Smith et al., 30 June 2020GlobalSystematic review9 publications on COVID−19‐positive pregnant women (n = 92)

Symptomatic: 67.4%

RT‐PCR inferior to CT‐based diagnosis: 31.7%

Mechanical ventilation and ICU: 1 patient

Maternal mortality: 0%

Caesarean delivery: 80%

Preterm births: 63.8%

Fetal distress: 61.1%

Admission to NICU: 76.92%

Low birth weight: 42.8%

Trocado et al., 31 July 2020ChinaSystematic review of case series and case reports8 publications

Most commonly reported symptoms: fever (55%), cough (38%), and fatigue (11%)

PROM: 5%

Fetal distress: 14%

Postpartum fever: 8%

Neonatal death: 2%

Severe neonatal asphyxia: 0%

Positive for Sars‐CoV‐2: 2%

Pneumonia but negative for SARS‐CoV‐2: 13%

Li et al., 26

March 2020

ChinaCase‐control study16 confirmed, 18 suspected

Fever and cough at the time of presentation in few patients

Most had COVID‐19 pneumonia

None had respiratory failure

All had cesarean delivery apart from 2

No infant with COVID‐19 infection

None developed severe neonatal complications

Chen et al., 12 February 2020ChinaRetrospective study9

7 patients had fever, sore throat, myalgia, and cough

None developed COVID‐19 pneumonia

None died

9 live births; no neonatal asphyxia

1 min Apgar score 8–9 and 5‐min score 9–10

No evidence of intrauterine transmission of disease

Liu et al., 4

March 2020

ChinaRetrospective study13

Cesarean delivery: 77%

Pregnancy complications included preterm delivery (46%), fetal distress (30%), PROM (10%), and stillbirth (10%)

Admission to ICU: 1 patient

No evidence suggested vertical transmission of disease

Yang et al., 36 April 2020ChinaRetrospective study13 confirmed

Mild symptoms with fever and dry cough, no expectoration

Cesarean delivery: 69%: vaginal delivery: 31%

No serious complications or death

57 newborns; all tested negative for SARS‐CoV‐2

Yang et al., 24 May 2020ChinaRetrospective study27

Viral pneumonia: 26

Severe pneumonia after delivery: 1 patient

No maternal deaths

Pre‐term delivery due to PROM: 1

24 live births, of which 23 were full‐term with good Apgar score

23 newborns tested negative for SARS‐CoV‐2 infection

1 newborn had high IgG and IgM levels 2 h after birth but tested negative in repeated RT‐PCR

Liu et al., 22 July 2020ChinaRetrospective study15

Mild symptoms in all patients with COVID‐19 pneumonia

No adverse effects

Cesarean delivery: 67%; vaginal delivery: 7%

No cases of neonatal death or asphyxia with normal Apgar scores at 1 min and 5 min

No neonates were infected

Abbreviations: ARDS, acute respiratory distress syndrome; CI, confidence interval; COVID‐19, coronavirus disease 2019, CRP, C‐reactive protein; ICU, intensive care unit; IgG, immunoglobulin G; IgM, immunoglobulin M; IUGR, intrauterine growth retardation; NICU, neonatal intensive care unit; PROM, premature rupture of membranes; RT‐PCR, reverse transcription polymerase chain reaction; SARS‐CoV‐2, severe acute respiratory symptom coronavirus 2.

Pregnancy outcomes in women with COVID‐19 seen in various studies Most commonly reported symptoms: fever and cough Maternal complications pooled prevalence: 45.0% (95% CI 24.0 –67.0) Admission to ICU: <20% Preterm infants pooled proportion: 23.0% (95% CI 11.0–39.0) Most frequent neonatal complications: pneumonia and respiratory distress syndrome Infected infants pooled proportion: 6.0% (95% CI 2.0–12.0) Most common presentations: fever, cough, and dyspnea (not requiring mechanical ventilation) Lymphopenia: 46% Elevated CRP: 48% Cesarean delivery: 72% Adverse pregnancy outcomes (preterm births and death/stillbirth or early terminated pregnancies): 27% Low birth weight: 7% Neonatal COVID‐19 infection: 1% Mild symptoms (95.6%), severe (3.6%), critical (0.8%) Mechanically ventilated: 1.5% Maternal mortality: 0.3% Cesarean delivery: 69.4% RT‐PCR positive: 1.6% Neonatal death: 0.4% Most presented at third trimester: 68% Most presenting symptoms: fever and cough Lymphocytopenia: 59% Elevated CRP: 70% Cesarean delivery: 91% Admission to ICU: 3 patients Intrauterine death: 1 IUGR: 1 Symptomatic: 67.4% RT‐PCR inferior to CT‐based diagnosis: 31.7% Mechanical ventilation and ICU: 1 patient Maternal mortality: 0% Caesarean delivery: 80% Preterm births: 63.8% Fetal distress: 61.1% Admission to NICU: 76.92% Low birth weight: 42.8% Most commonly reported symptoms: fever (55%), cough (38%), and fatigue (11%) PROM: 5% Fetal distress: 14% Postpartum fever: 8% Neonatal death: 2% Severe neonatal asphyxia: 0% Positive for Sars‐CoV‐2: 2% Pneumonia but negative for SARS‐CoV‐2: 13% Li et al., March 2020 Fever and cough at the time of presentation in few patients Most had COVID‐19 pneumonia None had respiratory failure All had cesarean delivery apart from 2 No infant with COVID‐19 infection None developed severe neonatal complications 7 patients had fever, sore throat, myalgia, and cough None developed COVID‐19 pneumonia None died 9 live births; no neonatal asphyxia 1 min Apgar score 8–9 and 5‐min score 9–10 No evidence of intrauterine transmission of disease Liu et al., March 2020 Cesarean delivery: 77% Pregnancy complications included preterm delivery (46%), fetal distress (30%), PROM (10%), and stillbirth (10%) Admission to ICU: 1 patient No evidence suggested vertical transmission of disease Mild symptoms with fever and dry cough, no expectoration Cesarean delivery: 69%: vaginal delivery: 31% No serious complications or death 57 newborns; all tested negative for SARS‐CoV‐2 Viral pneumonia: 26 Severe pneumonia after delivery: 1 patient No maternal deaths Pre‐term delivery due to PROM: 1 24 live births, of which 23 were full‐term with good Apgar score 23 newborns tested negative for SARS‐CoV‐2 infection 1 newborn had high IgG and IgM levels 2 h after birth but tested negative in repeated RT‐PCR Mild symptoms in all patients with COVID‐19 pneumonia No adverse effects Cesarean delivery: 67%; vaginal delivery: 7% No cases of neonatal death or asphyxia with normal Apgar scores at 1 min and 5 min No neonates were infected Abbreviations: ARDS, acute respiratory distress syndrome; CI, confidence interval; COVID‐19, coronavirus disease 2019, CRP, C‐reactive protein; ICU, intensive care unit; IgG, immunoglobulin G; IgM, immunoglobulin M; IUGR, intrauterine growth retardation; NICU, neonatal intensive care unit; PROM, premature rupture of membranes; RT‐PCR, reverse transcription polymerase chain reaction; SARS‐CoV‐2, severe acute respiratory symptom coronavirus 2.

MATERNAL OUTCOMES IN COVID‐19

As more and more data become available, it is becoming clear that maternal complications are common in pregnant women infected with SARS‐CoV‐2. , Maternal complications in mothers positive for COVID‐19 mostly included pneumonia. , , , Other reported complications are premature rupture of membranes (PROM), pre‐term deliveries, fetal distress, increased cesarean deliveries, lymphopenia, elevated C‐reactive protein, gestational hypertension, diabetes, pre‐eclampsia, placenta previa, oligohydramnios, polyhydramnios, hypothyroidism, abnormal umbilical cord, and sinus tachycardia. , In the past, SARS infection was found to increase the risk of fetal distress, and gestational diabetes and pre‐eclampsia are known to be higher in MERS infection, but no such correlation can be established for SARS‐CoV‐2. However, morbidity and mortality were found to be quite low in pregnant patients with COVID‐19. , , , , , , , In general, a systematic review of the literature shows that pregnant women positive for COVID‐19 with co‐morbidities are more likely to develop complications than those without.

Pneumonia

Pneumonia is one of the most common outcomes in pregnant women infected with COVID‐19. , , , Severe cases of pneumonia and respiratory conditions requiring ventilation support are one of the main causes of admission to hospital. , , However, a meta‐analysis of data from nine publications including 87 pregnant women with SARS‐CoV‐2 infection concluded that most pregnant women had mild to moderate COVID‐19 pneumonia, similar in clinical characteristics to that seen in an adult population. A retrospective study reported pneumonia among 96.3% of the pregnant patients with confirmed COVID‐19, with 3.7% of patients having severe pneumonia. In a case‐control study in China, 94% of the pregnant women with confirmed COVID‐19 showed typical chest computed tomography (CT) images of COVID‐19 pneumonia. However, the majority were asymptomatic upon admission to hospital, and none experienced severe respiratory failure during hospital stay and none died. In another single‐center Chinese study, mild pneumonia was diagnosed in all pregnant patients with COVID‐19 at the time of admission to hospital for delivery. However, no acute respiratory distress syndrome and aggravation of pneumonia were observed in the whole course. Even though all parturient patients required oxygen support, none required mechanical ventilation and the recovery was good. In their single‐center case‐control study (n = 55; 13 cases, 42 controls), Yang et al. reported that pregnant women with confirmed SARS‐CoV‐2 infection did not have expectoration, myalgia, or dyspnea; however, their pulmonary CT scan images resembled COVID‐19 pneumonia with ground‐glass opacity (46.2%), patch‐like shadow (23.1%), pleural effusion (38.5%), and pleural thickening (7.7%). Although the pleural effusion was significantly higher in pregnant women than non‐pregnant women, none showed any adverse effects. In a case series from Iran with nine pregnant women in the second or third trimester, the initial symptoms at the time of presentation in all of them were fever, dry cough, and dyspnea, and three patients later developed COVID‐19 pneumonia. Seven women died and two survived: one was critically ill and dependent on a ventilator; and the other was cured after a prolonged hospital stay. Neither of them had pre‐existing co‐morbidities.

Other adverse outcomes of COVID‐19 in pregnant women

Reports of worse clinical outcomes in pregnant women with COVID‐19, and even death, are also reported from countries outside of China, mainly the United States. In a study from the USA, out of 67.4% patients with symptoms of COVID‐19, 15% required antenatal admission. Among them, 9.3% developed severe disease and 4.7% developed critical disease requiring admission to the ICU and oxygen supplementation 6 days postpartum after a successful induction of labor. This was similar to the data for non‐pregnant patients with COVID‐19 (15% severe and 5% critical). A case series from the USA reported adverse outcomes in 28.5% pregnant patients with COVID‐19 including shortness of breath, dyspnea, cardiomyopathy, and moderately reduced left ventricular ejection fractions and hypokinesis, leading to admission to the ICU. However, another case series of pregnant women with confirmed COVID‐19 from the U.S.A reported no pregnancy complications or maternal deaths but reported one fetal demise at 14 weeks of gestation. Recently, the U.S. Centers for Disease Control and Prevention (CDC) presented a surveillance report of women (pregnant and non‐pregnant) with laboratory‐confirmed COVID‐19. The pregnant women are found to have a higher probability of hospitalization than non‐pregnant women (1.5% vs 0.9%), particularly admission to the ICU for mechanical ventilation (0.5% vs 0.3%). However, the risk of mortality was similar in both groups.

Fetal outcomes in pregnant women with COVID‐19

Neonatal outcomes of COVID‐19 mostly included preterm birth (39%), fetal distress (43%), intrauterine growth retardation (10%), miscarriage (2%), and perinatal death (7%). A systematic review by Yang et al. reported the following adverse fetal and neonatal outcomes of COVID‐19: preterm birth (21.3%); fetal distress (10.7%); stillbirth (1.2%); neonatal death (1.2%); and neonatal asphyxia (1.2%). Other studies reported 46%, 44.4%, 33.3%, 23.5%, 21%, and 4% cases of preterm delivery. , , , , , In contrast, a case series reported full‐term delivery in 100% of patients with COVID‐19. Fetal distress and PROM were reported in 22.2% of cases in a review, and neonatal distress in 5.3% cases of a single‐center study from China. Two other studies respectively mentioned fetal distress in 30% and 19% as well as PROM in 10% and 13% of patients with confirmed COVID‐19. , Chen et al. reported the incidence of abortions (spontaneous and induced) among 6% of pregnant women with COVID‐19 infection. The current data do not suggest a high risk of abortion or premature gestational loss, amniotic fluid abnormality, cyanosis, and congenital defects in neonates in mothers infected with COVID‐19.

CHANCES OF INTRAUTERINE VERTICAL TRANSMISSION OF SARS‐COV‐2 INFECTION

The risk of vertical transmission can theoretically exist in COVID‐19 since angiotensin‐converting enzyme 2 (ACE‐2) receptors are significantly expressed in the placenta with which SARS‐CoV‐2 may bind and enter. Intrauterine vertical transmission may typically occur through trans‐placenta, or ingestion or aspiration of cervicovaginal secretions. , Multiple studies confirmed the absence of SARS‐CoV‐2 isolates in the amniotic fluid, cord blood, breast milk sample, and neonatal throat swabs of the infected mother, indicating that intrauterine transmission, transmission during vaginal delivery, or through lactation was not possible. , , , , In the majority of the cases, the infected women gave birth to healthy babies with an Apgar score above 7 and negative reverse transcription polymerase chain reaction (RT‐PCR) test results. , , Furthermore, the placental pathology of three pregnant patients with COVID‐19 showed no morphological changes linked with the infection; all three placentas tested negative to RT‐PCR and there was no maternal‐fetal transmission. However, a systematic review and meta‐analysis of the available data provide no conclusive evidence of vertical transmisison of SARS‐CoV‐2 to date, except for a small risk in the third trimester. Therefore, actual risk of intrauterine vertical transmission can only be ascertained through RT‐PCR tests on amniotic fluid, placenta, and cord blood.

Benefits of screening of pregnant women during COVID‐19 pandemic

The diagnosis of COVID‐19 is based on comprehensive contact, travel history, and precise laboratory tests. According to WHO recommendations, RT‐PCR testing of samples from the respiratory tract should be performed for the identification and laboratory confirmation of cases of COVID‐19. Moreover, WHO has suggested the use of antibody‐detecting rapid tests for surveillance of the disease rather than for patient care. SARS‐CoV‐2 is highly contagious and can spread from both symptomatic and pre‐symptomatic patients. A high proportion of pre‐symptomatic patients with COVID‐19 exist worldwide. Due to a large number of pre‐symptomatic pregnant patients with COVID‐19, universal screening of pregnant women and implementing strict infection control measures to manage suspected or confirmed patients are essential to provide safety to both mothers and neonates as well as healthcare workers. According to the guidelines of the American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians and Gynaecologists (RCOG), every pregnant woman is at high risk and should take preventive measures including wearing masks, washing hands, and strictly maintaining social distancing when interacting with others. , ACOG and RCOG guidelines stated that COVID‐19 testing is critical for pregnant women to prevent transmission of the disease. , All pregnant women admitted to the hospital for maternity care should be asked for SARS‐CoV‐2 testing, irrespective of whether they have symptoms. For women who tested negative on admission, repeat testing should be offered 5–7 days later if they remain as inpatients. Pregnant women with suspected COVID‐19 or with symptoms suggestive of COVID‐19 should be tested on priority. Moreover, for pregnant women from areas of high prevalence, universal testing is strongly recommended due to an increased probability of presentation of asymptomatic patients to labor and delivery units from these areas. It is important to note that RT‐PCR is often not able to detect SARS‐CoV‐2 infection and therefore some pregnant women with COVID‐19 pneumonia may be missed unless a CT scan is performed.

STRENGTHS AND LIMITATIONS

The present narrative review has several limitations. Most of the studies included in the systematic reviews and meta‐analyses are from China. Thus, there is regional bias due to genetic and environmental factors and the level of medical care available in China. The majority of the literature is case reports, case series, or retrospective studies where the methodology is poor, and the evidence cannot be considered high level. There are very few case‐control studies and no large randomized trials comparing pregnant women positive for COVID‐19 with matched pregnant women without COVID‐19 infection. Additionally, like most narrative reviews, the present review also has a selection bias. However, the present narrative review does highlight the fact that COVID‐19 infection occurs in pregnant women and can be associated with poor maternal and fetal outcomes. Neonates born of pregnant women with COVID‐19 can get infected and therefore vertical transmission is possible. Additionally, RT‐PCR may not be a conclusive test to diagnose SARS‐CoV‐2 infection in pregnant women as some pregnant women with CT‐confirmed COVID‐19 infection are RT‐PCR negative. The present review also highlights that the majority of pregnant women get infected in the third trimester.

CONCLUSION

There is currently limited knowledge about SARS‐CoV‐2 infections in pregnancy. Based on the available data, the clinical characteristics of pregnant women with COVID‐19 seem to resemble those of non‐pregnant women. It cannot be conclusively said that SARS‐CoV‐2 infection increases the risk of maternal, fetal, and neonatal complications. Increased risks of maternal, fetal, and neonatal complications are noted in pregnant women positive for COVID‐19 with co‐morbidities. There are regional variations in the rates of adverse outcomes reported. Though vertical transmission is noted in very few cases, the review shows that it is possible. Additionally, the third trimester seems to be the most vulnerable period of infection and this aspect needs to be researched further to activate surveillance programs at the end of the second trimester. Further studies are warranted to assess whether the higher rates of adverse outcomes reported in mothers with COVID‐19 with co‐morbidities are due to the co‐morbidities or whether the SARS‐CoV‐2 infection worsens the disease course in these mothers. Multicenter global trials are required to look into the reasons for regional variations and understand why some regions report very few adverse outcomes. This would be helpful in developing a screening, diagnostic, and management algorithm to reduce adverse outcomes in mothers with COVID‐19.

AUTHOR CONTRIBUTIONS

DS was responsible for the design, planning, and writing of the manuscript. FK and TB were responsible for the literature data analysis for the review.

CONFLICTS OF INTEREST

The authors have no conflicts of interest.
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Journal:  Am J Transl Res       Date:  2021-12-15       Impact factor: 4.060

2.  Mild or Moderate COVID-19 during Pregnancy Does Not Affect the Content of CD34+ Hematopoietic Stem Cells in Umbilical Cord Blood of Newborns.

Authors:  Yu A Romanov; Yu A Kosolapova; V V Zubkov; D N Degtyarev; A Yu Romanov; T N Dugina; G T Sukhikh
Journal:  Bull Exp Biol Med       Date:  2022-09-05       Impact factor: 0.737

Review 3.  The COVID-19 Pandemic and Pregnancy: Impact on Mothers and Newborns.

Authors:  Jaime-Dawn E Twanow; Corinne McCabe; Margie A Ream
Journal:  Semin Pediatr Neurol       Date:  2022-05-21       Impact factor: 3.042

4.  Maternal Immune Activation and Interleukin 17A in the Pathogenesis of Autistic Spectrum Disorder and Why It Matters in the COVID-19 Era.

Authors:  Michael Carter; Sophie Casey; Gerard W O'Keeffe; Louise Gibson; Louise Gallagher; Deirdre M Murray
Journal:  Front Psychiatry       Date:  2022-02-17       Impact factor: 4.157

5.  Hearing test results of newborns born from the coronavirus disease 2019 (COVID-19) infected mothers: A tertiary center experience in Turkey.

Authors:  Gazi Yıldız; Didar Kurt; Emre Mat; Pınar Yıldız; Gülfem Başol; Elif Cansu Gündogdu; Betül Kuru; Bahtisen Topcu; Ahmet Kale
Journal:  J Obstet Gynaecol Res       Date:  2021-10-16       Impact factor: 1.697

6.  Tolerability of the BNT162b2 COVID-19 Vaccine during Pregnancy among Polish Healthcare Professionals.

Authors:  Wojciech Zdanowski; Agnieszka Markiewicz; Natalia Zdanowska; Janina Lipińska; Tomasz Waśniewski
Journal:  Vaccines (Basel)       Date:  2022-01-27

7.  Effect of the Covid 19 pandemic on depression and mother-infant bonding in uninfected postpartum women in a rural region.

Authors:  Özlem Erten; İsmail Biyik; Cenk Soysal; Onur Ince; Nadi Keskin; Yasemin Tascı
Journal:  BMC Pregnancy Childbirth       Date:  2022-03-19       Impact factor: 3.007

Review 8.  The Immunological Role of the Placenta in SARS-CoV-2 Infection-Viral Transmission, Immune Regulation, and Lactoferrin Activity.

Authors:  Iwona Bukowska-Ośko; Marta Popiel; Paweł Kowalczyk
Journal:  Int J Mol Sci       Date:  2021-05-28       Impact factor: 5.923

9.  Convalescent Plasma for Pregnant Women with COVID-19: A Systematic Literature Review.

Authors:  Massimo Franchini; Federico Prefumo; Gianpaolo Grisolia; Valentino Bergamini; Claudia Glingani; Marlene Pisello; Francesca Presti; Marco Zaffanello
Journal:  Viruses       Date:  2021-06-22       Impact factor: 5.048

10.  Characteristics and Outcomes of COVID-19 in Reproductive-Aged Pregnant and Nonpregnant Women in Osaka, Japan.

Authors:  Ling Zha; Tomotaka Sobue; Atsushi Hirayama; Taro Takeuchi; Kenta Tanaka; Yusuke Katayama; Sho Komukai; Takeshi Shimazu; Tetsuhisa Kitamura
Journal:  Int J Infect Dis       Date:  2022-01-29       Impact factor: 12.074

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