If you're pregnant and infected with COVID-19, there is an increased risk of negative outcomes for both you and your baby, according to a new study published in JAMA Pediatrics.
Expectant mothers with a COVID-19 diagnosis from 18 different countries were at higher risk for adverse outcomes, such as preeclampsia, infections, admission to hospital intensive care units and even death.
The risk of death for pregnant women with COVID-19 was 1.6%, which was 22 times higher than pregnant women who were not infected, according to the study.
Babies born to mothers infected with the novel coronavirus were also at somewhat higher risk of preterm birth and low birth weight, the study found.
"The results reported are sobering," wrote pediatrician Dr. Catherine Mary Healy in an accompanying editorial. Healy is an assistant professor at Baylor College of Medicine in Houston who specializes in pediatric infectious diseases.
'High risk of poor outcomes'
The study, which began in March 2020, and ended in October 2020, enrolled over 2,000 pregnant women from 43 medicalinstitutions in 18 countries: Argentina, Brazil, Egypt, France, Ghana, India, Indonesia, Italy, Japan, Mexico, Nigeria, North Macedonia, Pakistan, Russia, Spain, Switzerland, UK and the United States.
Healy wrote that she believed the study to be one of the largest to date, capturing reports from the different countries "in real time as the pandemic evolved from the earliest cases detected."
Of the 2,130 women in the study, 706 were diagnosed with COVID-19 — the remaining 1,424 women who were not infected were then matched by pregnancy gestation and demographic characteristics to reduce error.
Nearly 60% of the infected women were asymptomatic, meaning they had no fever or other signs of the virus. Still, Healy wrote, those women "were at higher risk of poor outcomes, such as preeclampsia or eclampsia, severe infections, admission to an intensive care unit ... and maternal death."
Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. Eclampsia is a severe complication of preeclampsia that causes seizures.
Pregnant women diagnosed with COVID-19 who were overweight or living with diabetes, heart disease, hypertension or chronic respiratory diseases were almost four times more likely to develop preeclampsia, the study found.
Why is pregnancy risky?
Why would pregnancy put women in greater danger from the virus? One reason is a decreased lung capacity for the woman as the baby grows.
"You can develop respiratory compromise, to the extent that you can't recover from it," Dr. Kjersti Aagaard, a maternal-fetal medicine specialist at Texas Children's Hospital, told CNN in January.
In addition, Aagaard — who is also Meyer professor chair in obstetrics and gynecology at Baylor College of Medicine — said a pregnant woman's heart pumps 1.5 times harder than it would normally to provide adequate blood for the baby and the placenta.
"That overaction of the heart, which we call a higher cardiac output, also renders pregnant women at risk from having heart failure problems, which can be a manifestation and potential cause of death from COVID-19 disease," she said.
Pregnant women may also be more likely to have an overenthusiastic immune system designed to protect the developing fetus, which can lead to the so-called cytokine storm — an overblown response by the immune system to COVID-19 that signals more severe disease and often the need for intensive care, Aagaard said.
And finally, there is an increased likelihood of blood clotting during pregnancy, which COVID-19 is known to make worse.
"Humans, like all placental mammals, run the risk of bleeding to death after that placenta separates off the wall of the uterus," Aagaard said. "So 4.5 million years of evolution is at our backs, helping us clot a little bit more effectively when we're pregnant."
Risks from COVID-19 vaccine appear low
A recent study of 3,958 pregnant women between 16 and 54 years old who received the Moderna or Pfizer vaccine found few serious side effects from the vaccination.
The most common was pain at the injection site, which the study found occurred more frequently in pregnant vaccine recipients. However, expectant mothers who were vaccinated reported fewer headaches, muscle aches, chills and fever.
As part of the study, data gathered by the US Centers for Disease Control and Prevention's Vaccine Adverse Event Reporting System (VAERS) between December 14, 2020 and February 28, 2021, was analyzed.
There were 221 pregnancy-related adverse events reported during that time frame, including 46 miscarriages. The study compared those events to data on negative pregnancy outcomes before the pandemic.
"Although not directly comparable, calculated proportions of adverse pregnancy and neonatal outcomes in persons vaccinated against COVID-19 who had a completed pregnancy were similar to incidences reported in studies involving pregnant women that were conducted before the COVID-19 pandemic," the study said.
Major medical groups in the United States have been urging pregnant women to consider being vaccinated against COVID-19.
"U.S. regulatory bodies and medical experts have clearly stated that all eligible pregnant individuals should have the choice to receive the vaccine," said Dr. Christopher Zahn, vice president of practice activities for the American College of Obstetricians and Gynecologists, in a prior CNN interview.
"There's really no theoretical reason to believe it's going to cause harm to either the mother, or her unborn child, and we're very confident it's going to provide considerable benefits to both the mother and the baby," added Dr. Richard Beigi, who sits on ACOG's Immunization, Infectious Disease, and Public Health Preparedness Expert Work Group.
For any pregnant woman who is hesitant to be vaccinated, "adherence to public health guidance regarding mask wearing, handwashing, and social distancing are first and necessary steps," Healy wrote.
Pregnant women should also avoid crowds and activities with high risks of transmission, such as eating in restaurants, she added.