A Birth Defects Insights Blog
By Sonja Rasmussen, MD, MS, Past President of the Society for Birth Defects Research and Prevention
This blog is also available on Medium.com.
So much has changed in the past year – who could have predicted that terms like lockdown, herd immunity, and personal protective equipment (PPE) would become part of the general public’s vocabulary?! The same is true regarding what we know about COVID-19 and pregnancy. Looking back to a year ago, in February of 2020, the news was beginning to be dominated by reports of a novel virus that had emerged in Wuhan, China. By February, I had been following the virus for a while. Because of my years working at the Centers for Disease Control and Prevention (CDC) in the pandemic planning unit, I followed STAT news reporter Helen Branswell on Twitter. On December 31, 2019, she tweeted, “Hopefully this is nothing out of the ordinary. But a @ProMED-mail posting about “unexplained pneumonias” in China is giving me #SARS flashbacks” (Figure). The possibility of a new respiratory virus gave me chills. Could this be the “big one”– the nightmare scenario of a novel respiratory virus spreading easily from person to person – that kept us up at night? Of course, it didn’t take long for us to recognize that this WAS the big one that we’d been preparing for. Two days later, Helen tweeted, “Not liking the look of this.” Helen is an incredibly savvy science reporter -- I had been interviewed by her several times in my days at CDC, and she was a knowledgeable (and tough) interviewer. If Helen was worried, I was worried, too.
I was especially concerned about the effects of this new virus on pregnant people and their babies. I had retired from CDC in June of 2018 after 20 years, during which I had worked on multiple infectious disease outbreaks – 2009 H1N1 influenza, H7N9 influenza, Middle East Respiratory Syndrome (also caused by a coronavirus), Ebola, and most recently Zika virus. Working on these outbreaks had taught us about the importance of studying the effects on the pregnant people and their babies. During the 2009 H1N1 influenza pandemic, we learned that the virus had severe effects on pregnant people – pregnant people made up about 5% of deaths in the United States from 2009 H1N1 flu, even though only ~1% of the general population is pregnant. And during the Zika virus outbreak, we learned that babies born after a Zika-infected pregnancy are at risk for severe birth defects, because the virus could pass from the mother across the placenta to the fetus and cause damage.
After Helen’s January 2 tweet, things moved rapidly. On January 7 Chinese scientists identified a new coronavirus as the cause of those mysterious pneumonias, on January 9 China shared the genetic sequence of the virus, and on January 21 the first case was confirmed in the United States. On January 27 I reached out to my close friend and colleague Dr. Denise Jamieson about writing a paper on what we might expect during pregnancy based on what we knew about the effects of SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), two previous coronaviruses that had caused severe disease. Denise, now chair of the Department of Gynecology and Obstetrics at Emory, and I had worked together for many years on issues related to infections and pregnancy when we were both at CDC. A few days later on January 30, the World Health Organization declared the outbreak a Public Health Emergency of International Concern. When I look back at the first draft of the paper I sent to Denise on February 1, a lot has changed. At that time, the virus and disease were referred to as 2019 Novel Coronavirus (2019-nCoV) and 2019-nCoV infection, respectively; only 6 cases had been diagnosed in the United States; and no cases of infection during pregnancy had been reported. On February 11, the disease got an official name: Covid-19 (“Co” and “Vi” to indicate that it is caused by a coronavirus, “d” to indicate that it causes disease, and 19 to note the year that the infection had emerged). After many updates, I pushed the “submit” button on our paper on February 12, and by the time we completed the revisions 5 days later, the virus had also gotten a name: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and 2 reports that described 18 pregnancies had been published. We quickly added the new information and a comment to the paper -- given that this was a rapidly evolving situation, we encouraged obstetricians to follow the CDC website to stay updated. The paper was accepted on February 18 and was published online on February 24.
Almost a year later, on February 8, 2021, we published an update on COVID-19 in pregnancy in JAMA to summarize what we know now about COVID-19 during pregnancy. Although early data were unclear as to whether pregnancy was a risk factor for severe disease, later data showed that pregnant people are at increased risk for admission to an intensive care unit (ICU), for requiring invasive ventilation (a machine to help with breathing), and for death, compared to women of reproductive age. COVID-19’s effects on the newborn are less clear. Several, but not all, studies have suggested that infants born after a SARS-CoV-2-infected pregnancy are more likely to be born preterm. Although the virus can be passed from the mother across the placenta to the fetus, that appears to occur rarely, and no evidence has suggested an increased risk for birth defects. Transmission of the virus through breastfeeding also appears to be unlikely. Early on, concerns were raised about transmission from an infected breastfeeding mother to the baby after birth, but it appears that with appropriate precautions (wearing a mask and practicing careful hand and breast hygiene), transmission can be prevented.
The most exciting news in the area of COVID-19 is the availability of safe and effective vaccines. Currently two vaccines, made using messenger RNA (mRNA) technology, are available in the United States (US), and others are expected to be available soon. As is often the case for clinical trials of medications, pregnant people were excluded from the clinical trials for COVID-19 vaccines. However, given what is known about the safety of other vaccines during pregnancy and about how mRNA vaccines work, there is no reason to expect that these vaccines would pose a risk to the fetus. Therefore, several groups, including CDC, American College of Obstetricians and Gynecologists (ACOG), and the Society for Maternal-Fetal Medicine (SMFM) have come forward to say that pregnant persons who meet criteria for receiving COVID-19 vaccine may choose to receive the vaccine. Pregnant persons might benefit from a discussion with their physician to weigh the benefits and potential risks of the vaccine during pregnancy, although this discussion should not be required before vaccination. Several studies are in progress to better understand the effects of COVID-19 vaccines during pregnancy, so more information is expected soon. Data on the effects of COVID-19 vaccines on the breastfed baby are also not available. However, given what is known about the safety of breastfeeding after other types of vaccines and the well-recognized benefits of breastfeeding to the infant and mother, CDC, ACOG, and SMFM are all reassuring about receiving the vaccine while breastfeeding.
It’s been a whirlwind year, filled with uncertainty for all including pregnant people. Much has been learned about COVID-19 and pregnancy over the past year, but many questions remain. For example, beyond prematurity, are there other effects on a baby born after a SARS-CoV-2 infected pregnancy? And more data are needed on COVID-19 vaccines during pregnancy – for example, does giving a COVID-19 vaccine during pregnancy provide protection to the newborn, as has been seen with influenza and Tdap vaccines? I encourage researchers to continue to challenge themselves to answer these critical questions and applaud those clinicians who translate the currently available data to their patients. By working together, I am hopeful that many of these questions will be answered soon.
About the Author
Sonja A. Rasmussen, MD, MS, is professor of pediatrics, obstetrics and gynecology, and epidemiology at the University of Florida College of Medicine and College of Public Health and Health Professions. She joined the University of Florida after 20 years at the Centers for Disease Control and Prevention (CDC), where she worked on public health responses to 2009 H1N1 influenza, Middle East Respiratory Syndrome (MERS), Ebola, and Zika viruses.
More about the Society for Birth Defects Research and Prevention (BDRP)
To understand and prevent birth defects and disorders of developmental and reproductive origin, BDRP promotes multi-disciplinary research and exchange of ideas; communicates information to health professionals, decision-makers, and the public; and provides education and training.
Scientists interested in or already involved in research related to topics mentioned in this blog are encouraged to join BDRP and/or attend or present their research at the Society’s virtual 61st Annual Meeting this summer (abstracts due March 31). BDRP is the premier source for cutting-edge research and authoritative information related to birth defects and developmentally mediated disorders. Our members include those specializing in cell and molecular biology, developmental biology and toxicology, reproduction and endocrinology, epidemiology, nutritional biochemistry, and genetics, as well as the clinical disciplines of prenatal medicine, pediatrics, obstetrics, neonatology, medical genetics, and teratogen risk counseling. In addition, BDRP publishes the scientific journal, Birth Defects Research. Learn more at http://www.birthdefectsresearch.org. Find BDRP on LinkedIn, Facebook, Twitter and YouTube.