The study, published in the Journal of Maternal-Fetal And Neonatal Medicine, adds a new layer onto the growing body of research showing the potential complications COVID-19 can cause for both pregnant people and babies.
As COVID-19 continues to affect more expectant people in the United States, especially those who are unvaccinated, here are seven questions answered about pregnancy and the coronavirus.
1. Are pregnant people at higher risk?Yes, pregnant people are at higher risk for complications from COVID-19.
Since the onset of the pandemic, more than 127,000 pregnant people have tested positive for COVID-19, 22,000 pregnant people have been hospitalized nationwide and at least 171 pregnant people have died as result of COVID-19, according to federal data.
COVID-19 causes a two-fold risk of admission into intensive care and a 70% increased risk of death for pregnant people, according to the Centers for Disease Control and Prevention (CDC).
Research published last month in the American Journal of Obstetrics and Gynecology, a medical journal, also found that pregnant people infected with the delta variant are more likely to have severe COVID-19 cases, and the variant leads to even worse outcomes for unvaccinated pregnant people.
2. What risks does COVID-19 bring to the fetus?Pregnant people with COVID-19 are more likely to experience preterm birth, or delivering the baby earlier than 37 weeks, according to the CDC.
Poor pregnancy outcomes, such as pregnancy loss, have also been reported. There have been at least 266 pregnancy losses in the U.S. since the onset of the pandemic, according to federal data.
Infants with COVID-positive mothers had two times greater odds of developing any type of adverse health complication during the birth process compared to infants with COVID-negative mothers, according to the research published in Journal Of Maternal-Fetal And Neonatal Medicine.
3. Is the COVID-19 vaccine safe for pregnant people?Yes, the vaccines are safe for people who are pregnant, breastfeeding, trying to get pregnant or might become pregnant in the future, according to data compiled over the past nearly one year.
Both the Pfizer and Moderna vaccines use mRNA technology, which does not enter the nucleus of the cells and doesn't alter the human DNA. Instead, it sends a genetic instruction manual that prompts cells to create proteins that look like the virus as a way for the body to learn and develop defenses against future infection.
They are the first mRNA vaccines, which are theoretically safe during pregnancy, because they do not contain a live virus.
Messenger RNA vaccines for COVID-19, such as those produced by Moderna and Pfizer, showed no obvious safety concerns for pregnant women, according to a preliminary report published in April in the New England Journal of Medicine.
The Johnson & Johnson vaccine uses an inactivated adenovirus vector, Ad26, that cannot replicate. The Ad26 vector carries a piece of DNA with instructions to make the SARS-CoV-2 spike protein that triggers an immune response.
This same type of vaccine has been authorized for Ebola, and has been studied extensively for other illnesses -- and for how it affects women who are pregnant or breastfeeding.
The CDC as well as the nation's two leading health organizations focused on the care of pregnant people -- American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) -- have all issued guidelines calling on all pregnant people to get vaccinated against COVID-19, citing the safety and efficacy of the vaccines.
The COVID-19 vaccines can be taken during any trimester.
Just 25% of pregnant people in the U.S. between the ages of 18 and 49 are currently vaccinated with at least one dose, according to the CDC.
4. What precautions should pregnant people take?The most important thing pregnant people can do to protect themselves is to get vaccinated, and to make sure their loved ones are vaccinated too, medical experts say.
Pregnant people who are fully vaccinated should wear a face mask indoors when in public in areas of substantial or high transmission, avoid crowds and poorly ventilated indoor spaces and wash hands often with soap and water, according to the CDC.
Unvaccinated pregnant people should get vaccinated and continue masking until fully vaccinated, while also following safety guidelines like avoiding crowds and poorly ventilated indoor spaces, washing hands often with soap and water and staying 6 feet apart from people not in their households, according to the CDC.
5. Should pregnant people travel?There is no guidance that pregnant people should not travel, so it's ultimately a personal decision.
Pregnant people should consult with their doctors first. Factors to consider include where you're considering traveling, how far along in your pregnancy you are and what your backup plan would be.
When traveling, pregnant people should wear a face mask that covers their nose and mouth.
In addition to considering whether the country in question has seen a significant influx of COVID-19 cases, think about the situation on ground. Has travel within the country been disrupted? How would you feel about potentially being quarantined upon returning to the United States? Is there a risk you could be grounded due to canceled flights or quarantines and not be able to travel home? Would you have access to medical care at your destination?
The U.S. State Department provides travel advisories that include up-to-date recommendations about which countries have reported cases of COVID-19 and how widespread infections have been.
6. Can coronavirus be transferred to the fetus?There is still more research to be done to determine whether a pregnant person could pass the virus to her fetus before, during or after delivery.
One small study released last year found that a pregnant person infected with COVID-19 might be able to spread it to their fetus.
According to the CDC, some newborns have tested positive for COVID-19 shortly after birth but it is not known if the newborns got the virus before, during, or after birth.
7. Is it safe for a person with COVID-19 to breastfeed?It is safe, in general, to breastfeed when you have COVID-19, according to both the CDC and the American College of Obstetricians and Gynecologists (ACOG).
The CDC recommends that people with COVID-19 wash their hands before breastfeeding and wear a mask when breastfeeding and whenever they are within 6 feet of the baby.
It is not likely that COVID-19 can pass through breast milk.
Recent studies have shown though that people who are vaccinated against COVID-19 may be able to pass along protection from the virus to their infant through breastfeeding.