The Bottom Line

This pages serves to highlight the latest objective research, news, and professional guidance and recommendations regarding pregnancy-related health.

As of December 2021, COVID-19 and other respiratory infections (e.g. influenza) are the current major health-related issues that could adversely affect pregnant women. Women should also take note that Respiratory Syncytial Virus (RSV) cases are beginning to increase in the U.S.

Influenza and COVID-19 are both considered potentially serious infections in pregnancy. Although RSV is a relatively minor infection among adults, researchers recommend pregnant women ask to be tested for this common virus if other diagnoses are ruled out.

This page will highlight COVID-19 infection and vaccine-safety data as it is published/released, as well as evidence-based information on how women can prevent, manage, and treat respiratory infections during pregnancy.

Additional highlights and research updates on other topics related to pregnancy are also listed below. Women should talk to their health care provider (HCP) if they have any questions.

Note: Unless ongoing, highlights are kept on this page for approximately 30 days before being removed or added to a permanent Topic page.

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Latest Page Updates

Pages updated within the past week (as of November 28, 2021):

Photo by Toa Heftiba on Unsplash

Latest Research/Recommendations

November 20, 2021: A pre-print published on November 20 sought to determine the durability of COVID-19 antibodies in infants after maternal infection and after maternal vaccination during pregnancy. In the vaccinated group, 94% (58/62) of infants had detectable anti-spike IgG antibodies at 2 months, and 60% (18/30) had detectable levels at 6 months. In contrast, 8% (1/12) of infants born to those infected with SARS-CoV-2 in pregnancy had detectable anti-spike IgG at the 6-month timepoint. The study concluded that vaccination resulted in significantly higher maternal and cord titers at delivery and significantly greater antibody persistence in infants at 6 months, compared to natural infection.

November 15, 2021: Meta-analysis found that fetal hiccups and regular episodes of vigorous movement were associated with decreased odds of late stillbirth. Learn more about fetal hiccups here.

November 8, 2021: In a prospective cohort study, pregnant individuals who consumed low and moderate levels of caffeinated beverages early in the second trimester within current guidelines of less than 200 mg/d was associated with lower risk for gestational diabetes and lower glucose levels at screening, compared with women who did not drink caffeinated beverages. 

November 4, 2021: A review of 23 studies determined that pregnant and lactating populations experienced vaccine-related reactions at similar rates to the general population. No increased risk of adverse obstetrical or neonatal outcomes were reported. One study demonstrated that pregnant individuals were less likely to experience COVID-19 when vaccinated.

November 1, 2021: Animal study determined that gadolinium-based contrast agents, intravenous drugs used for CT and MRI imaging during pregnancy, can cause uterine contractions. This could explain some of the known adverse effects of these drugs when used in pregnancy. Learn more.

October 25, 2021: Study determined that COVID-19 infection early in pregnancy does not appear to raise the risk of pregnancy loss compared to those who do not contract the infection in early pregnancy.

October 21, 2021: Study analyzed pregnancies that occurred in four ongoing phase 1, phase 2, and phase 3 clinical trials of the AstraZeneca COVID-19 vaccine in three countries. Any pregnancies that occurred after vaccination were recorded and followed up until 3 months after birth. Pregnancy outcomes were reviewed by the independent data and safety monitoring board.

"We found no evidence of an association between reduced fertility and vaccination with [AZD1222]...Furthermore, compared with women who received the control vaccine, there was no increased risk of miscarriage and no instances of stillbirth in women vaccinated before pregnancy in global clinical trials of [AZD1222]."

October 21, 2021: U.S. FDA authorizes Moderna and Johnson & Johnson booster vaccinations, along with "mix & match" boosters:

  • The use of a single booster dose of the Moderna COVID-19 Vaccine may be administered at least 6 months after completion of the primary series to individuals:

    • 65 years of age and older

    • 18 through 64 years of age at high risk of severe COVID-19

    • 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2

  • The use of a single booster dose of the Janssen (Johnson and Johnson) COVID-19 Vaccine may be administered at least 2 months after completion of the single-dose primary regimen to individuals 18 years of age and older.

  • The use of each of the available COVID-19 vaccines as a heterologous (or “mix and match”) booster dose in eligible individuals following completion of primary vaccination with a different available COVID-19 vaccine.

  • A single booster dose of the Pfizer-BioNTech COVID-19 Vaccine may be administered at least 6 months after completion of the primary series to individuals 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2. Learn more.

October 21, 2021: A meta-analysis of thirty-two cohort studies and seven case-control studies determined that folic acid supplementation during pregnancy had a positive impact on offspring's neurodevelopmental outcomes, including improved intellectual development and reduced risk of autism traits, ADHD, behavioral, and language problems.


COVID-19 and Vaccines

Background: In March 2020, the World Health Organization officially declared a worldwide pandemic of a new respiratory infection called coronavirus 2019 (COVID-19), more formally “severe acute respiratory syndrome coronavirus 2” or SARS-CoV-2.

As of December 1, 2021, the U.S. Centers for Disease Control and Prevention (CDC) estimates the virus has caused approximately 48,497,243 illnesses and 780,131 deaths.

States with the highest case rates per 100,000 people (as of November 28): Michigan, Minnesota, New Hampshire, North Dakota, and Wisconsin.

General COVID-19 information and pregnancy health: According to currently available case series and cohorts as of November 2021, data indicates pregnant women are not more susceptible to the disease than non-pregnant women, and fetal and symptomatic neonatal infection appear to be rare events.

Weekly COVID-19 Pregnancy Data from CDC:

  • Total Cases: 148,327

  • Hospitalized: 25,178 (data only available for 121,973)

  • Total Deaths: 241

*As of November 29, 2021

These numbers likely do not include all pregnant women with COVID-19 in the United States and must be interpreted with caution.

However, pregnant women who contract COVID-19 appear to be at higher risk of complications from the disease than non-pregnant women of reproductive age. These complications include Intensive Care Unit admission, the need for mechanical ventilation, and the need for extracorporeal membrane oxygenation (ECMO). Learn more.

There are currently three COVID-19 vaccines in the United States approved and/or authorized for use: Comirnaty (formerly known as Pfizer-BioNTech), Moderna (SpikeVax in Canada, Europe), and Johnson & Johnson/Janssen.

Photo by Mufid Majnun on Unsplash

The FDA does not have a specific recommendation regarding whether one vaccine is more preferable over another, to include during pregnancy and lactation. It is recommended by numerous expert panels and obstetric organizations that women choose for themselves whether they would like to be vaccinated, after consultation with their HCP.

In the U.K., the Pfizer-BioNTech, SpikeVax, Janssen, and Vaxzevria (formerly Oxford-AstraZeneca) vaccines are currently authorized by its vaccine regulator, the Medicines and Healthcare products Regulatory Agency.

Read more on COVID-19, pregnancy, and more detailed vaccine information and guidance from the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine, the Society of Obstetricians and Gynecologists' of Canada, the U.K. Royal College of Obstetricians and Gynaecologists, and The Royal Australian and New Zealand College of Obstetricians and Gynaecologists here.


In the United States, influenza season begins on October 1 and can last until May.

Influenza Activity in the U.S:

As of November 22, 2021, seasonal influenza activity in the United States remains low, but the number of influenza virus detections reported by clinical and public health laboratories and the percent of patient visits for influenza-like illness has increased in recent weeks. There is currently no data yet specific to pregnancy for this current season.

Source: CDC FluView Tracker.

Relaxed COVID-19 mitigation measures (such as stay-at-home orders, or mask mandates) may result in an increase in flu activity during the 2021–2022 flu season, compared to last year. While common respiratory viruses such as RSV did not spread as much as usual during the 2020-2021 flu season as in past seasons, data from the National Respiratory and Enteric Surveillance System (NREVSS) showed an increase in these viruses’ activity during the summer, outside of their usual seasonal increases. 

According to a CDC report published in July 2021, "reduced circulation of influenza viruses during the 2020-2021 year might affect the severity of the upcoming influenza season [starting in October 2021] given the prolonged absence of ongoing natural exposure to influenza viruses."

"Lower levels of population immunity, especially among younger children, could portend more widespread disease and a potentially more severe epidemic when influenza virus circulation resumes."

Pregnant women are recommended to receive a flu vaccine during any trimester due to the risk of severe infection. Learn more about the safety and effectiveness of flu vaccines in pregnancy here.

All flu vaccines this season are quadrivalent (four component), meaning they are designed to protect against four different flu viruses. Per the CDC, COVID-19 and influenza vaccines can be given at the same time.


Women should talk to their HCP if they any questions related to any of the updates above. Not all pregnant women who contract COVID-19 or influenza will have serious illness. However, there is currently no way to determine which women may experience a more severe course of either infection.

It is recommended that pregnant women:

  • Seek care immediately or dial 911 if experiencing a medical emergency. Emergency symptoms can include trouble breathing, persistent pain or pressure in the chest, new confusion, inability to wake or stay awake, or bluish lips or face. This is not an inclusive list, and women should always call their HCP or visit an emergency room when necessary.

  • Report any and all symptoms of a respiratory infection to their HCP, to include cough, fevershortness of breath, and diarrhea

  • Avoid unnecessary traveling, use of public transportation, and contact with sick people

  • Wear a mask (to protect others) in public settings

  • Follow personal and social distancing rules

  • Regularly wash hands for at least 20 seconds (if soap and water are not readily available, use a hand sanitizer that contains at least 60% alcohol)

  • Avoid touching their eyes, nose, and mouth with unwashed hands.

  • Do not skip prenatal care appointments or other health appointments that may be necessary

  • Make sure to have at least a 30-day supply of prescription medications

  • Learn about stress and coping

  • Get adequate sleep and physical exercise

  • Quit smoking (risk factor for infection)

  • Go outside in open areas for walks, fresh air, and a change of scenery

Any pregnant woman who has traveled in a state or country with a high rate of COVID-19 infection or who has had close contact with an individual with confirmed infection should be tested and quarantined.

Pregnant women are also advised to see their HCP immediately or call 911 if they experience:

  • Difficulty breathing or shortness of breath

  • Persistent pain or pressure in the chest or abdomen

  • Persistent dizziness, confusion, inability to arouse

  • Seizures

  • Not urinating

  • Severe muscle pain and/or weakness

  • Fever or cough that improves but then returns or worsens (may indicate pneumonia)

  • High fever that is not responding to acetaminophen or other anti-fever medication (acetaminophen is not an NSAID)

Women should refer to the CDC and ACOG COVID-19 web pages below for additional information.


Total cases in the United States/COVID tracker (U.S. Centers for Disease Control and Prevention)

COVID-19 Home Page (U.S. Centers for Disease Control and Prevention)

ACOG Statement on COVID-19 and Pregnancy (American College of Obstetricians and Gynecologists; June 2020)

Coronavirus (COVID-19), Pregnancy, and Breastfeeding: A Message for Patients (American College of Obstetricians and Gynecologists)

The Management of Respiratory Infections During Pregnancy (Immunology and Allergy Clinics of North America; 2006)


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