The pandemic has created a for pregnant people and .
Stress levels among expectant mothers have soared. are five times as likely as uninfected pregnant people to require intensive care and 22 times as likely to die. Infected moms are four times as likely to have a .
Yet some of the pandemic鈥檚 greatest threats to infants鈥 health may not be apparent for years or even decades.
That鈥檚 because babies of covid-infected moms are to be born very prematurely, which increases the danger of infant mortality and long-term disabilities such as , as well as a child鈥檚 risk of adult disease, including , .
Studies have linked and to developmental and psychiatric conditions such as , and .
鈥淪ome of these conditions do not show up until middle childhood or early adult life, but they have their origins in fetal life,鈥 said Dr. Evdokia Anagnostou, a child neurologist at Holland Bloorview Kids Rehabilitation Hospital and a pediatrics professor at the University of Toronto.
For fetuses exposed to covid, the greatest danger is usually not the coronavirus itself, but the mother鈥檚 immune system.
Both severe covid infections and the strain of the pandemic can expose fetuses to , which can occur when a mother鈥檚 immune system is fighting a virus or when .
Prenatal inflammation 鈥渃hanges the way the brain develops and, depending on the timing of the infection, it can change the way the heart or kidneys develop,鈥 Anagnostou said.
Although health officials have strongly recommended covid for pregnant people, only .
At least 150,000 pregnant people have been diagnosed with covid; more than 25,000 of them have been hospitalized, and 249 have died, according to the .
Although most babies will be fine, even a small increase in the percentage of children with special medical or educational needs could have a large effect on the population, given the huge number of covid infections, Anagnostou said.
鈥淚f someone has a baby who is doing well, that is what they should focus on,鈥 Anagnostou said. 鈥淏ut from a public health point of view, we need to follow women who experienced severe covid and their babies to understand the impact.鈥
Learning From History
Researchers in the and are already studying to see whether these children than those conceived or born before 2020.
Previous crises have shown that the challenges fetuses face in the womb 鈥 such as maternal infections, hunger, stress and hormone-disrupting chemicals 鈥 , as well as that of , said Dr. Frederick Kaskel, director of pediatric nephrology at the Children’s Hospital at Montefiore.
People whose mothers were pregnant during surges in the 1918 influenza pandemic, for example, had poorer health throughout their lives, compared with Americans born at other times, said John McCarthy, who is a medical student at Albert Einstein College of Medicine and co-wrote a recent with Kaskel.
Researchers don鈥檛 know exactly which moms were infected with pandemic flu, McCarthy said. But women who were pregnant during major surges 鈥 when infection was widespread 鈥 had children with higher rates of heart disease or diabetes. These children were also .
Because organ systems develop during different periods of pregnancy, fetuses exposed during the first trimester may face different risks than those exposed toward the end of pregnancy, McCarthy said. For example, people born in the fall of 1918 were ; that may reflect an exposure to the pandemic in the third trimester, while the kidneys were still developing.
Nearly two years into the covid pandemic, researchers have begun to of infants exposed to covid infections and stress before birth.
Although Anagnostou noted that it鈥檚 too early to reach definitive conclusions, 鈥渢here is evidence that babies born to moms with severe covid infections have changes to their immune system,鈥 she said. 鈥淚t鈥檚 enough to make us worry a little bit.鈥
Damaging a Fetal Security System
The good news about the coronavirus is that it seldom , the organ tasked with protecting a developing fetus from and providing it with oxygen. So moms with covid rarely give the virus to their children before birth.
That鈥檚 important, because some viruses that directly infect the fetus 鈥 such as Zika 鈥 can cause , said Dr. Karin Nielsen-Saines, a specialist in pediatric infectious diseases at UCLA鈥檚 David Geffen School of Medicine.
But studies also suggest that inflammation from a mother鈥檚 covid infection can injure the placenta, said Dr. Jeffery Goldstein, an assistant professor of pathology at Northwestern University鈥檚 Feinberg School of Medicine. In a study , Goldstein and his co-authors found that placentas from covid-infected moms had more abnormal blood vessels than placentas from patients without covid, making it harder for them to deliver sufficient oxygen to the fetus.
can also lead to , a serious complication of pregnancy that can cause a mother鈥檚 blood pressure to spike.
occurs when blood vessels in the placenta don鈥檛 develop or function properly, forcing the mother鈥檚 heart to work harder to get blood to the fetus, which may not receive enough oxygen and nutrients. Preeclampsia also predisposes women to later in life.
Rewiring the Immune System
In some cases, covid also appears to rewire a baby鈥檚 immune response, Nielsen-Saines said.
In an October study in the journal , Nielsen-Saines and her co-authors found that infants born to people with severe covid infections had a different mix of immune cells and proteins than other babies. None of the newborns tested positive for the coronavirus.
The immune changes are concerning, Nielsen-Saines said, because this pattern of immune cells and proteins has previously been found in infants with respiratory problems and in some cases poor neurodevelopment.
Notably, all the babies in her study appear healthy, said Nielsen-Saines, who plans to to see whether these early signals translate into developmental delays, such as problems talking, walking or interacting with others.
鈥淗ow big of a difference does any of this make in the baby?鈥 asked Anagnostou. 鈥淲e won鈥檛 know for a few years. All we can do is try to be as prepared as possible.鈥
Increasing the Risk for Boys
Boys could face higher risks from covid, even before birth.
Males are generally more vulnerable than females as fetuses and newborns; they鈥檙e more likely to be born and to. Preterm boys also have a higher risk of .
But coronavirus infection poses special dangers, said Sabra Klein, a professor of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health.
That鈥檚 because boys are disproportionately affected by conditions linked to maternal infections. Boys are four times as likely as girls to be diagnosed with or , for example, while men are 75% more likely than women to develop .
Scientists don鈥檛 fully understand why boys appear more fragile in the womb, although testosterone 鈥 which can dampen immune response 鈥 may play a role, said Dr. Kristina Adams Waldorf, a professor of obstetrics and gynecology at the University of Washington.
Men generally than women and more often develop . suggests boys with covid are more likely than girls to become seriously ill or develop a rare called multisystem inflammatory syndrome.
New research on covid could help illuminate this vulnerability.
In a , researchers found that the sex of a fetus influences the way its placenta responds to covid, as well as how its mother鈥檚 immune system responds.
Pregnant people infected with covid made fewer antibodies against the coronavirus if they were carrying male fetuses than if they were carrying females. Mothers also transferred fewer antibodies to boys than to girls, said Dr. Andrea Edlow, senior author of the study and a maternal-fetal medicine specialist at Massachusetts General Hospital.
When examining the placentas of male fetuses after delivery, researchers found changes that could leave boys less protected against damaging inflammation.
The sex of a fetus can influence its mother鈥檚 response to other illnesses, as well.
For example, research shows that pregnant women with asthma have worse symptoms if they鈥檙e . Women carrying males are slightly more likely to develop .
Edlow said her findings raise questions about the 鈥渃ross talk鈥 between mother and baby. 鈥淭he mom鈥檚 immune system is sensing there is a male fetus,鈥 Edlow said. 鈥淎nd the fetus is actively communicating with the mom鈥檚 immune system.鈥
Boosting Toxic Stress
and have increased dramatically during the pandemic.
That鈥檚 concerning because chronic stress , affecting the babies of both infected and , Anagnostou said.
Studies consistently show that infants born to mothers who experience significant stress during pregnancy have higher rates of short- and long-term health damage 鈥 including heart defects and obesity 鈥 than babies born to women with less stress.
鈥淲e know that inflammation directly influences the way a baby鈥檚 brain develops,鈥 said Elinor Sullivan, an associate professor in psychiatry at Oregon Health & Science University.
Lockdowns, travel restrictions and physical distancing left many pregnant women without the support of family and friends. The stress of losing , or a home further heightens the risks to moms and babies, said Sullivan, who is following children born during the pandemic for five years.
In research that has not yet been published, Sullivan found that babies of women who were pregnant during the pandemic showed more sadness and negative emotions in the first year of life compared with infants of women who were pregnant before the pandemic.
The findings show the importance of helping and protecting pregnant people before and after delivery, said Sullivan, who conducted that found women who received more social support were less depressed.
Italian researchers are also on infants鈥 behavior, as well as the way their genes are regulated.
Although stress-related inflammation doesn鈥檛 alter the structure of a baby鈥檚 genes, it can influence whether they鈥檙e turned on and off, said Livio Provenzi, a psychologist at the C. Mondino National Institute of Neurology Foundation in Pavia, Italy.
In of 163 mother-baby pairs, he found differences in how genes that regulate the stress response were activated. Genes that help people respond to stress were more in babies whose moms reported the most stress during pregnancy. The same moms also reported that their babies when they were 3 months old.
Researchers usually prefer to make in-person observations of babies as they interact with their mothers, Provenzi said. But because of the pandemic, Provenzi asked mothers to fill out questionnaires about infant behavior. He plans to observe mothers and babies in person when the children are 12 months old.
While is the best way to protect them and their fetuses from the virus, Anagnostou said, society needs to do more to preserve expectant mothers鈥 mental health.
鈥淲e can鈥檛 escape the fact that we鈥檝e lived through two years of a pandemic,鈥 Anagnostou said. 鈥淏ut we can think about opportunities for reducing the risk.鈥
[Editor鈥檚 note: In this article, study participants were known to be cisgender women. And KHN uses terms like 鈥渕other,鈥 鈥渕om鈥 and 鈥渕aternal鈥 to refer generally to the expectant parent or the one who has given birth.]
