Da Newsletter da Evidence Based Birth

 

Hello

It’s been 6 weeks since our last COVID-19 and pregnancy newsletter.

In this edition of the Evidence Based Birth® COVID-19 Newsletter, we provide a new overview of the research on COVID-19 and pregnancy to date, focusing on key findings and recommendations.

**Feel free to forward this email to any friends, family, clients, or colleagues who might find it helpful. If you’re a healthcare worker, feel free to print this off to share at the nurse’s station! Anyone can subscribe to receive these updates by visiting evidencebasedbirth.com/covid19

The archive of this newsletter will also be posted on that page.

Today’s questions (answered in a Q&A section at the bottom of this email) include:

  • Do we know what the overall pre-term birth rate was in the U.S. for 2020, and how that might compare to other years?
  • I have a history of COVID in early pregnancy, and now my doctor is recommending that I take either aspirin or an anticoagulant for the rest of pregnancy. Is there any research on this?

To ask a question for consideration for future newsletters, submit your question here.

Don’t forget that our COVID-19 resource & pregnancy page includes archives of these newsletters (including past Q & A’s), a sample informed consent form to refuse mother-newborn separation, our virtual doula directory, a free birthing crash course, a link to find our comprehensive EBB Childbirth Class online, and other info you might find useful. You can access that page here.


Research Update for January 21, 2021

  • Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19).
  • Black, Latinx, and Indigenous pregnant and nonpregnant individuals are bearing the burden of the pandemic. These groups have higher rates of COVID-19 infections, hospitalizations, and severe outcomes, including death. Racial and ethnic health inequity in the pandemic is due to long-standing structural racism that put brown and black bodies at increased risk of getting sick and dying—not because of their biology, but because of discrimination in all sectors of life (aka systemic racism).

Numbers Update from Johns Hopkins University

As of January 21, 2021, there are over 96 million confirmed and probable cases of COVID-19 around the world. The highest number of cases is still in the U.S. (over 24 million), followed by India, Brazil, Russia, the United Kingdom, France, Italy, Turkey, Spain, and Germany.

Prevention

  • Pregnant people are advised to follow the same recommendations as nonpregnant people for avoiding exposure to SARS-CoV-2. These recommendations from the CDC include:
    • Wear a mask over your nose and mouth
    • Stay 6 feet away from people who don’t live in your household
    • Avoid crowded places
    • Meet in outdoor spaces when possible and try to ventilate indoor spaces
    • Wash hands often
    • Cover coughs and sneezes
    • Clean and disinfect frequently touched surfaces
    • Be alert for symptoms of COVID-19
  • Prenatal and postpartum care appointments are important to keep; however, depending on your individual circumstances, it might be appropriate to delay some appointments or meet virtually. Elective ultrasounds are not recommended (ACOG, 2020). GBS screening is still recommended between 36 weeks, 0 days and 37 weeks, 6 days of pregnancy. However, some care settings are giving people instructions on how to self-collect a vaginal-rectal swab to limit in-person exposure during the pandemic (ACOG, 2020).

Vaccines

  • Many vaccines are being developed, but pregnant and lactating individuals have been excluded from every trial so far. This means we do not have any data yet on the maternal, fetal, or newborn effects of these vaccines.
  • The two vaccines that are currently authorized and recommended to prevent COVID-19 in the U.S. are the Pfizer-BioNTech vaccine and Moderna’s vaccine. They are both messenger RNA (mRNA) vaccines that do not contain live virus.
  • In the U.S., the SMFM (12/21), ACOG (12/21), and the CDC (12/28) recommended that COVID-19 vaccines should not be withheld from pregnant/lactating individuals who are otherwise eligible for the vaccine and desire vaccination.
  • In the U.K., on December 3, the Joint Committee on Vaccination and Immunization initially stated “JCVI favours a precautionary approach, and does not currently advise COVID-19 vaccination in pregnancy.” However, the JCVI updated their guidance on December 30 and now advises that “extremely clinically vulnerable” pregnant people discuss the option of vaccination with their care provider. They listed specific underlying conditions that put pregnant people at very high risk of experiencing serious complications from COVID-19:
    • Solid organ transplant recipients
    • Those with severe respiratory conditions including cystic fibrosis and severe asthma
    • Those who have homozygous sickle cell disease
    • Those receiving immunosuppression therapies sufficient to significantly increase risk of infection
    • Those receiving dialysis or with chronic kidney disease (stage 5)
    • Those with significant congenital or acquired heart disease
  • The JCVI also now advises that pregnant health care workers and pregnant workers in residential facilities can discuss the option of vaccination. In addition, they say that breastfeeding/chestfeeding parents should be offered vaccination if they are otherwise eligible.
  • The Royal College of Obstetricians & Gynecologists released a handout on COVID-19 vaccination and pregnancy (1/12/21). You can access this vaccine info sheet here.

Clinical Symptoms and Testing

  • COVID-19 symptoms are similar between pregnant and nonpregnant patients; however, some symptoms with infection appear to be less common during pregnancy, especially fever.
  • The U.S. PRIORITY study (Pregnancy CoRonavIrus Outcomes RegIsTrY) is an ongoing prospective nationwide study in the United States of pregnant or recently pregnant people. The most common symptoms in 594 symptomatic patients who tested positive for SARS-CoV-2 infection were cough (20%), sore throat (16%), body aches (12%), and fever (12%) (Afshar et al. 2020). Half of everyone had their symptoms resolve by 37 days, but symptoms lasted for ≥8 weeks in 25% of PRIORITY participants. In the PRIORITY study, 95% of participants were outpatients. The researchers are working to increase enrollment of Latina, Black, and Native American patients. These groups are currently underrepresented in the study (60% of study participants are White) which limits generalizability.
  • Data from the CDC that included more hospitalized pregnant people with COVID-19 show increased rates of symptoms (50% had cough, 32% had fever, 37% had muscle aches, 24% has chills, 43% had headache, 26% head shortness of breath, 28% had sore throat, 14% had diarrhea, 20% had N/V, 8% had abdominal pain, 13% had runny nose, 22% had new loss of taste or smell, 14% had fatigue, 2% had wheezing, and 4% had chest pain (Zambrano et al. 2020).
  • To treat fever and pain, acetaminophen (Tylenol) is preferred over NSAIDs (aspirin, ibuprofen/Motrin/Advil) because of possible worsening of symptoms with COVID-19 (Berghella and Hughes, 2020). Low-dose aspirin is still recommended for preeclampsia prevention as medically indicated, but may not be appropriate for pregnant and recently pregnant patients with suspected or confirmed COVID; care should be individualized (ACOG, 2020).
  • Systematic reviews suggest that the majority of pregnant people who test positive during universal screening are without symptoms (most asymptomatic, but some pre-symptomatic) (Berghella and Hughes, 2020).
  • COVID-19 diagnosis is done with nucleic acid amplification testing (NAAT), most commonly with a reverse-transcription polymerase chain reaction (RT-PCR) assay, which detects SARS-CoV-2 RNA from the upper respiratory tract. PCR tests are considered the gold standard for testing.
  • Antigen tests are another type of diagnostic test. They detect a specific protein in SARS-CoV-2. Antigen tests are sometimes used first, but these tests are less sensitive, so negative antigen tests should usually be confirmed with NAAT if there is clinical suspicion of COVID-19. The majority of rapid tests so far have been antigen tests; however, there are now rapid PCR-based tests available in some care settings.
  • False-negative tests are possible, so a negative RT-PCR test may need to be repeated if there is high clinical suspicion of COVID-19.
  • False-positives have also been reported, but they are thought to be less common than false-negatives.

Maternal Outcomes

  • There is no evidence that pregnancy increases the risk of getting infected with SARS-CoV-2
  • Definitions according to the National Institutes of Health:
    • Mild illness is considered symptoms without difficulty breathing or abnormal chest imaging
    • Moderate illness is evidence of lower respiratory disease by clinical assessment or imaging and a saturation of oxygen (SaO2) ≥94% on room air at sea level.
    • Severe illness is respiratory frequency >30 breaths per minute, SaO2 <94% on room air at sea level, ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) < 300, or lung infiltrates >50%
    • Critical illness is respiratory failure, septic shock, and/or multiple organ dysfunction
  • Most (>90%) of people infected during pregnancy recover before they give birth and without needing hospitalization for COVID-19 (Berghella and Hughes, 2020). It is reassuring that the majority of pregnant people with COVID-19 either have no symptoms or mild illness that does not require hospitalization.
  • However, pregnancy has been shown to increase the risk of severe or critical COVID-19. Given the growing evidence, the CDC now includes pregnant people in its “increased risk” category for COVID-19 illness. Unfortunately, the evidence in limited by large amounts of missing data on pregnancy status, race/ethnicity, and info on symptoms and underlying medical conditions (Zambrano et al. 2020).
  • According to the latest U.S. surveillance data from the CDC (with over 400,000 symptomatic females of reproductive age), pregnant people with symptomatic COVID-19 appear to be at increased risk for ICU admission, invasive ventilation, extracorporeal membrane oxygenation (ECMO, a life support machine) and death compared to nonpregnant females of the same age with symptomatic COVID-19 (Zambrano et al. 2020). Still, the absolute risk of severe or critical illness and death for pregnant patients is low—even lower than the absolute risk of these outcomes during the H1N1 influenza pandemic (ACOG, 2020).
  • In the CDC analysis, the absolute risks for invasive ventilation and death for pregnant versus nonpregant people of the same age and sex were 2.9 versus 1.1 per 1,000 and 1.5 versus 1.2 per 1,000, respectively. ECMO was used rarely but at a higher rate with pregnancy (0.7 versus 0.3 per 1,000). The absolute risk of ICU admission was noticeably increased (10.5 versus 3.9 per 1,000); however, this may be due in part to differences in care management during pregnancy.
  • Remember, these absolute risks apply to people with lab-confirmed, symptomatic COVID-19; we don’t know if the risk of these outcomes is increased during pregnancy for people with asymptomatic infection or with symptoms that are so mild they do not seek medical care.
  • Risk factors for severe or critical COVID-19 during pregnancy are similar to the risk factors in the general population (Westnedge et al. 2021). They include age ≥35 years, BMI ≥30, hypertension, and diabetes (preexisting and gestational) (Allotey et al. 2020; ACOG, 2020).
  • Importantly, Black and Hispanic individuals who are pregnant are disproportionately affected by COVID-19—not because of their biology, but because of systemic racism creating inequitable opportunities for health.
  • Timing of birth with COVID-19 should be individualized. Importantly, COVID-19 infection is not an indication for Cesarean, induction, or operative vaginal birth. When possible, it’s best to wait to give birth until after testing negative. Then, there is less chance of passing the infection to health care workers and to the newborn in the postpartum period.
  • However, people with term pregnancies who have mild COVID-19 may wish to give birth sooner rather than later to avoid the risk of giving birth with more severe COVID-19 (should the disease worsen).
  • Severely ill patients at least 32 weeks of pregnancy with COVID-19 pneumonia may benefit from early birth. But it’s not clear whether giving birth improves the birthing person’s respiratory disease (Berghella and Hughes, 2020).
  • Maternal COVID-19 is linked to an increased risk of Cesarean. A report from the UK Obstetric Surveillance System (UKOSS) on pregnant people admitted to the hospital with confirmed COVID-19 in the UK found that 59% of people gave birth by Cesarean (Knight et al. 2020). About half of these were for maternal or fetal compromise and half were for other obstetric reasons (e.g., progress in labor, planned repeat Cesarean).
  • A large systematic review estimated that about 65% of pregnant people with suspected or confirmed COVID-19 gave birth by Cesarean (Allotey et al. 2020). Many of the studies in this review (24/77) came from China, where the Cesarean rate with COVID-19 was very high early in the pandemic.
  • U.S. surveillance data of pregnant people with laboratory-confirmed SARS-CoV-2 infection reported that among nearly 4,000 birthing people, the overall Cesarean rate was 34%, which is slightly higher than the U.S. Cesarean rate in 2019 (32%) (Berghella and Hughes, 2020).
  • Wider implications of the pandemic for maternal health include increased risk of mental health distress and intimate partner violence. Care providers should be on heightened alert for these issues and look for ways to help clients manage stress, anxiety, and depression.

Newborn Outcomes

  • Maternal COVID-19 has been linked to an overall increased risk of preterm birth, although individual countries have reported seeing decreased rates of preterm birth or no change in preterm birth rates.
  • A systematic review of 77 studies from more than a dozen different countries, including over 11,000 pregnant and recently pregnant people with suspected or confirmed COVID-19, estimated that about 17% of births were preterm (Allotey et al. 2020). This was a three times greater risk of preterm birth with COVID-19 compared to those without the disease. However, most of these preterm births were medically caused (iatrogenic). The spontaneous preterm birth rate was only 6%, which is similar to the rate observed before the pandemic. It’s thought that complications from COVID-19 (e.g., pneumonia) increase the risk of Cesarean and preterm birth because providers intervene in hopes of improving the maternal respiratory condition. However, there is no evidence that planned early birth improves maternal outcomes with severe or critical COVID-19 (Berghella and Hughes, 2020).
  • U.S. surveillance data of pregnant people with laboratory-confirmed SARS-CoV-2 infection reported that among 3,912 live births with known gestational age, 12.9% were preterm (<37 weeks) (Woodworth et al. 2020). This rate is higher than the reported 10.2% among the general U.S. population in 2019. Please see the Q&A section at the bottom of this newsletter for more discussion of pre-term birth rates during the pandemic.
  • The U.S. PRIORITY study has, so far, not detected a difference in poor outcomes, including preterm birth, NICU admission, and respiratory disease, between infants (n=263) born to birthing parents testing positive (n=179) versus those testing negative (n=84) (Flaherman et al. 2020). A study with more racial and ethnic diversity also did not detect a difference in poor outcomes (using a combined outcome of preterm birth, severe preeclampsia, or Cesarean for abnormal GHR) by maternal COVID-19 status (Adhikari et al. 2020).
  • There is no evidence suggesting an increased risk of congenital anomalies or any problems with the baby’s development.
  • There is also no evidence suggesting that infection in early pregnancy increases the risk of miscarriage. (Data on first and second trimesters are limited.)
  • Vertical transmission (transmission from the pregnant person to the baby before or during birth) has been reported in a few cases but it is thought to be rare. Researchers still do not understand the mechanisms by which vertical transmission occurs (Westnedge et al. 2021). A few placental infections and very early newborn infections have been reported; however, most placentas studied so far had no evidence of infection. Importantly, there is no evidence that the risk of vertical transmission is affected by mode of birth, method of feeding or rooming in. The vast majority (over 95%) of newborns born to infected parents have been asymptomatic or with only mild infection at birth. It is reassuring that severe or critical COVID-19 is rare with newborns (Westnedge et al. 2021).
  • A large U.S. observational study found that the rate of early newborn infection among infants born to a parent who tested positive was 3%; most of the infected babies were born to parents with no symptoms or mild symptoms (Adhikari et al. 2020).
  • There is no evidence that the risk of stillbirth increases with COVID-19 infection; however, the risk does appear to increase among patients hospitalized with a COVID-19 infection.
  • Analysis of hospitalization data from England did not show an increase in stillbirths in England during the pandemic when compared with the same months in the previous year (Stowe et al. 2020).
  • In the U.S., data from the CDC show a higher stillbirth rate among pregnant people hospitalized with COVID-19 compared to the overall population of pregnant people with lab-confirmed infection (3% versus 0.4%) (Panagiotakopoulos et al. 2020; Woodworth et al. 2020). For comparison, the overall rate of stillbirth in the U.S. is 0.6%. The increase in stillbirth among hospitalized COVID-19 patients may be related to maternal illness, medical intervention to treat COVID-19, and/or disruptions in prenatal care during the pandemic.
  • There have been reports of problems with placental function from COVID-19 infection. However, more data is needed before we know how widespread a problem this is, and whether it’s clinically significant.

Treatment

  • Corticosteroid use to help prevent preterm birth is likely safe for pregnant people with COVID-19, and corticosteroid use for severe or critical maternal COVID-19 may also be beneficial (Westnedge et al. 2021).
  • ACOG recommends that dexamethasone, a corticosteroid, be used for pregnant people with COVID-19 who are receiving supplemental oxygen or are mechanically ventilated, and that dexamethasone should not be withheld for treatment of COVID-19 due to pregnancy status.
  • Similarly, UpToDate guidance for clinicians advises that “In pregnant women who meet criteria for use of glucocorticoids for maternal treatment of COVID-19 and also meet criteria for use of antenatal corticosteroids for fetal maturity, we suggest administering the usual doses of dexamethasone (four doses of 6 mg given intravenously 12 hours apart) to induce fetal maturation and continue dexamethasone to complete the course of maternal treatment for COVID-19 (6 mg orally or intravenously daily for 10 days or until discharge, whichever is shorter).”
  • The evidence for dexamethasone treatment comes from the RECOVERY trial, a large, multicenter, RCT for patients hospitalized with COVID-19 in the U.K. (RECOVERY Collaborative Group et al. 2020). The trial showed that dexamethasone resulted in lower 28-day mortality among people receiving either mechanical ventilation or oxygen but not among those receiving no respiratory support. Even though only six pregnant people were included in the trial, guidance supports dexamethasone for use with infected pregnant people who are receiving supplemental oxygen or are mechanically ventilated because of possible life-saving benefits.
  • Pregnancy is a hypercoagulable state (meaning there is an increased tendency toward blood clotting), so people who are pregnant or in the postpartum period have increased risk of thromboembolism (a blood clot that is carried by the blood stream and plugs a blood vessel) compared with nonpregnant people (ACOG, 2020). COVID-19 is also linked to increased blood clotting and increased risk of thromboembolism, especially in ICU patients. Therefore, recommendations are that pregnant patients hospitalized with severe or critical COVID-19 should be treated with prophylactic-dose anticoagulation, if there are no contraindications to its use (ACOG, 2020; Berghella and Hughes, 2020). Clinicians should also have a low threshold for investigating possible thromboembolic events in COVID-19 patients during pregnancy and postpartum (Westnedge et al. 2021). Please see the Q&A section at the bottom of this newsletter for more discussion of anticoagulant drugs.
  • Remdesivir, an antiviral medication, is recommended for pregnant patients who would otherwise be candidates for the treatment. It has been used with severely ill pregnant patients without causing harm to the fetus (Berghella and Hughes, 2020).

Giving Birth

  • ACOG guidelines suggest, “In both the inpatient and outpatient settings, it is recommended that the number of visitors be reduced to the minimum necessary, for example, those essential for the pregnant individual’s well-being (emotional support persons).” Importantly, they say, “Labor, delivery, and postpartum support may be especially important to improve outcomes for individuals from communities traditionally underserved or mistreated within the health care system. In considering visitation policies, institutions should be mindful of how restrictions might differentially and negatively affect these communities, which in many areas are also disproportionately affected by COVID-19.”
  • Professional guidelines acknowledge that it may not be feasible to wear a mask during labor, especially during second stage labor (ACOG, 2020). Wearing a mask could make pushing difficult and forceful exhalation may also make the mask significantly less effective. For this reason, those caring for birthing people should use appropriate PPE.
  • Delayed cord clamping is still best practice when the birthing parent has COVID-19 (ACOG, 2020). The cord should remain unclamped for up to five minutes or when cord pulsation ceases. There is no evidence that delayed cord clamping increases the risk of giving the virus to the baby, and there are substantial known risks to early cord clamping. The care provider should wear appropriate PPE.

Rooming in and Infant Feeding

  • There are many established benefits to rooming in, including increased success breastfeeding and parent-infant bonding. Studies have not found a difference in the rate of transmission when newborns are separated from infected parents versus kept together in the same room. Guidelines now state that newborns should “ideally” be kept together with their infected parent, and that “Decisions about temporary separation should be made in accordance with the mother’s wishes.” (ACOG, 2020).
  • Birthing parents with COVID-19 should be encouraged to breastfeed/chestfeed, but should wear PPE (Westnedge et al. 2021). It is not known whether the virus can be transmitted through breastmilk. One case report detected SARS-CoV-2 RNA in breastmilk, but the viral particles may not have been infectious; most breastmilk samples from positive parents have been negative.
  • Healthy, uninfected birthing parents and newborns are advised to consider early hospital discharge after birth (after 1 day with uncomplicated vaginal births and after 2 days with Cesarean births depending on recovery status) (ACOG, 2020).

Professional Guidance and Clinical Recommendations

  • Several professional organizations have issued guidance on pregnancy issues during the pandemic. You can access professional guidance at acog.orgSMFM.org, and rcog.org.uk.
  • Also, UpToDate.com has made their COVID-19 content free. They have a page devoted to COVID-19 and pregnancy.

Q & A Section

Question: Do we know what the overall pre-term birth rate was in the U.S. for 2020, and how that might compare to other years?

Answer: No, the most recent year of birth data from the U.S. Centers for Disease Control (CDC) is 2019. The CDC National Center for Health Statistics (NCHS) released their latest data brief (No. 387) in October 2020 with key findings from the 2019 data. The overall rate of preterm birth rose to 10.23% in 2019, an increase over the 2018 rate of 10.02%.

We don’t know yet if the U.S. preterm birth rate rose in 2020, although early findings suggest that it may have. The CDC has been collecting info on pregnancy and infant outcomes among pregnant people with lab-confirmed infections through SET-NET (the Surveillance for Emerging Threats to Mothers and Babies Network). Among 3,912 live births to infected parents, 12.9% were preterm (<37 weeks) (Woodworth et al. 2020). As you can see, this is higher than the U.S. preterm birth rate among the general population in 2018 and 2019, and if enough pregnant people experienced infection, this could possibly contribute to a higher preterm birth rate in 2020.

Individual studies have been mixed on whether they found a difference in preterm births during the pandemic. Decreases in preterm births have been reported in several European countries, sometimes alongside increases in stillbirth. But even within countries, the impact of the pandemic on preterm birth likely varies in sub-populations based on social and economic factors.

Question: I have a history of COVID in early pregnancy, and now my doctor is recommending that I take either aspirin or an anticoagulant for the rest of pregnancy. Is there any research on this or guidelines to support this practice?

Answer: We have not seen any evidence to support the prophylactic (preventative) use of aspirin among pregnant people with a history of COVID-19 earlier in pregnancy but without other clinical indications for the treatment. However, recommendations mention that aspirin should continue to be offered to pregnant and postpartum parents as medically indicated during the pandemic (ACOG, 2020). Perhaps your doctor is recommending aspirin for a non-COVID related medical indication? Low-dose aspirin is most commonly recommended during pregnancy to pregnant people at moderate to high risk of preeclampsia.

As we mentioned earlier in this newsletter, aspirin may not be appropriate for pregnant people with suspected or confirmed COVID-19 because of evidence that NSAIDs (including aspirin) potentially worsen COVID symptoms.

We are also not aware of any evidence (yet) to support thromboprophylaxis with anticoagulants among pregnant people with a history of COVID-19 earlier in pregnancy but without other clinical indications for the treatment. People with active COVID-19 infections during pregnancy (particularly with severe or critical disease) may benefit from anticoagulation treatment, but the treatment is only recommended for those who are hospitalized because of their COVID-19 disease (Berghella and Hughes, 2020). People hospitalized because of their COVID-19 infections may be advised to continue thromboprophylaxis for 10 days following hospital discharge or longer if they remain ill from their infection. But if you had COVID-19 in early pregnancy and it did not require hospitalization, then your doctor may be recommending anticoagulants because you have non-COVID related risk factors for blood clots (also known as venous thromboembolisms, or VTEs).

Whenever care providers recommend intervention, you should always feel empowered to ask them if their advice is based on a research study, a clinical guideline, or their professional medical opinion. Also, keep in mind that as the pandemic progresses, new research may come out that provides us with new insights on this topic.

This concludes the research update for January 21, 2021. We hope you found it helpful! Our next research update will come out in March 2021.

If you would like to submit a follow-up question for our consideration to include in upcoming newsletters, you can submit your question here.

Sincerely,

The Research Team at Evidence Based Birth®


References

Adhikari, E. H., Moreno, W., Zofkie, A. C., et al. Pregnancy Outcomes Among Women With and Without Severe Acute Respiratory Syndrome Coronavirus 2 Infection. JAMA Netw Open. 2020;3(11):e2029256. Click here.

Afshar, Y., Gaw, S. L., Flaherman, V. J., et al. (2020). Clinical Presentation of Coronavirus Disease 2019 (COVID-19) in Pregnant and Recently Pregnant People. Obstet Gynecol. 2020 Dec;136(6):1117-1125. Click here.

Allotey, J., Stallings, E., Bonet, M., et al… for PregCOV-19 Living Systematic Review Consortium (2020). Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. BMJ (Clinical research ed.), 370, m3320. Click here.

American College of Obstetricians and Gynecologists (2020). COVID-19 FAQs for obstetricians-gynecologists, obstetrics. Washington, DC: ACOG. Available at: https://www.acog.org/clinical-information/physician-faqs/covid-19-faqs-for-ob-gyns-obstetrics. Retrieved January 7, 2020.

Berghella, V. and Hughes, B. (2020). UpToDate: Coronavirus disease 2019 (COVID-19): Pregnancy Issues and Antenatal care. Click here.

Flaherman, V. J., Afshar, Y., Boscardin, W. J., et al. (2020). Infant Outcomes Following Maternal Infection With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): First Report From the Pregnancy Coronavirus Outcomes Registry (PRIORITY) Study, Clinical Infectious Diseases, ciaa1411. Click here.

Knight, M., Bunch, K., Vousden, N., et al. Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study. BMJ 2020; 369:m2107. Click here.

Panagiotakopoulos, L., Myers, T. R., Gee, J., et al. (2020). SARS-CoV-2 Infection Among Hospitalized Pregnant Women: Reasons for Admission and Pregnancy Characteristics — Eight U.S. Health Care Centers, March 1–May 30, 2020. MMWR Morb Mortal Wkly Rep 2020;69:1355–1359. Click here.

RECOVERY Collaborative Group, Horby, P., Lim, W. S., et al. (2020). Dexamethasone in Hospitalized Patients with Covid-19 – Preliminary Report. N Engl J Med. 2020 Jul 17:NEJMoa2021436. Click here.

Stowe, J., Smith, H., Thurland, K., et al. (2020). Stillbirths During the COVID-19 Pandemic in England, April-June 2020. JAMA 2020. Click here.

Wastnedge, E. A. N., Reynolds, R. M., van Boeckel, S. R., et al. (2021). Pregnancy and COVID-19. Physiol Rev. 2021 Jan 1;101(1):303-318. Click here.

Woodworth, K. R., CDC COVID-19 Response Pregnancy and Infant Linked Outcomes Team, COVID-19 Pregnancy and Infant Linked Outcomes Team (PILOT), et al. (2020). Birth and Infant Outcomes Following Laboratory-Confirmed SARS-CoV-2 Infection in Pregnancy – SET-NET, 16 Jurisdictions, March 29-October 14, 2020. MMWR Morb Mortal Wkly Rep. 2020 Nov 6;69(44):1635-1640. Click here.

Zambrano, L. D., Ellington, S., Strid, P., CDC COVID-19 Response Pregnancy and Infant Linked Outcomes Team, et al. (2020). Update: Characteristics of Symptomatic Women of Reproductive Age with Laboratory-Confirmed SARS-CoV-2 Infection by Pregnancy Status – United States, January 22-October 3, 2020. MMWR Morb Mortal Wkly Rep. 2020 Nov 6;69(44):1641-1647. Click here.