Newborn Diseases Every Pregnant Person Needs on Their Radar

If you’re pregnant, trying to conceive, or just considering having kids in the near future, stay aware of these dangerously "silent" infections.

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If the past year and a half has proven one thing, it's that viruses can be wildly unpredictable. In some cases, COVID-19 infections produced a host of jarring symptoms, from high fevers to a loss of taste and smell. In other instances, symptoms were barely detectable, or entirely nonexistent. And for some people, "long-haul" COVID-19 symptoms persisted days, weeks, and even months post-infection.

And that variability is exactly how viruses are engineered to work, says Spencer Kroll, M.D., Ph.D., nationally recognized cholesterol and lipid disease expert. "One of the great debates in medicine is whether a virus is a living entity. What is clear is that many viruses hijack a body's cells, inserting their DNA code where it can lay quiet for years. They can then cause trouble long after the person has been infected." (

But while the COVID-19 virus is mainly transmitted through small particles and droplets breathed out by an infected person (in other words, wearing a mask is key!), some viruses are transmitted in other, more subtle ways.

Case in point: diseases that can be passed from a pregnant person to an unborn child. As Dr. Kroll points out, even if you're not currently aware that you are infected with a virus, and it remains dormant in your system, it could be passed on to your unborn child unknowingly.

Here are a handful of "silent" viruses to stay on the lookout for if you're an expecting parent or trying to conceive.

Cytomegalovirus (CMV)

Cytomegalovirus is a type of herpes virus occurring in 1 out of every 200 births that can result in a host of harmful birth defects, such as hearing loss, brain defects, and eyesight issues. To make matters worse, only about nine percent of women have heard of the virus, according to Kristen Hutchinson Spytek, president and co-founder of the National CMV Foundation. CMV can affect all ages, and just over half of all adults will have been infected with CMV before age 40, she adds, though it's usually harmless in folks who aren't immunocompromised. (

But when the virus is passed onto a baby from a pregnant person who is infected, things can become problematic. Of all children born with a congenital CMV infection, one in five develop disabilities like vision loss, hearing loss, and other medical issues, according to the National CMV Foundation. They'll often struggle with these ailments for their entire lives because there is currently no vaccine or standard treatment or vaccine for CMV.

That being said, newborns can be screened for the disease within three weeks of birth, says Pablo J. Sanchez, M.D., a pediatric infectious diseases specialist and principal investigator in the Center for Perinatal Research at The Research Institute. And if CMV is diagnosed within that period, Spytek says that certain antiviral medications can often reduce the severity of hearing loss or improve developmental outcomes. "The damage previously caused by congenital CMV cannot be reversed, however."

Pregnant people can take steps to potentially prevent spreading the disease to an unborn child, says Spytek. Here are the National CMV Foundation's top tips:

  1. Don't share food, utensils, drinks, straws, or toothbrushes, and don't put a child's pacifier in your mouth. This goes for anyone, but especially with children between the ages of one and five, as the virus is particularly common among young children in day care centers.
  2. Kiss a child on the cheek or head, rather than their mouth. Bonus: Babies' heads smell ah-mazing. It's a scientific truth. And feel free to give all the hugs!
  3. Wash your hands with soap and water for 15 to 20 seconds after changing diapers, feeding a young child, handling toys, and wiping a young child's drool, nose, or tears.


If you have a feline friend, there's a chance you've heard of a virus called toxoplasmosis. "It's a disease caused by a parasite," explains Gail J. Harrison, M.D., professor in the Department of Pediatrics and Pathology and Immunology at the Baylor College of Medicine. It's most commonly present in cat feces, but can also be found in uncooked or undercooked meats and contaminated water, utensils, cutting boards, etc. The most common way to ingest these particles is by getting them in your eyes or mouth (which makes frequent hand-washing especially important).

While many people develop temporary mild flu-like symptoms or no symptoms at all from the disease, when passed to an unborn baby, it can result in a number of complications, says Dr. Harrison. Children born with congenital toxoplasmosis can develop hearing loss, eyesight issues (including blindness), and mental disabilities, according to the Mayo Clinic. (It's important to note, however, that toxoplasmosis typically goes away on its own and can be treated with certain medications in adults.)

If you're infected with the virus during your pregnancy, there's a chance you'll pass it on to your unborn baby. According to the Boston Children's Hospital, that chance is roughly 15 to 20 percent if you're infected during your first trimester, and upwards of 60 percent during the third trimester.

There are a variety of treatments available for babies born with congenital toxoplasmosis, but your best bet is to take serious prevention steps during pregnancy, according to the Mayo Clinic. Here, the Mayo Clinic offers a handful of tips:

  1. Try to stay out of the litter box. You don't need to get rid of Mr. Muffins entirely, but try to have another member of the household clean their feces. What's more, if the cat is an outdoor cat, keep them indoors throughout your pregnancy and only feed them canned or bagged food (nothing raw).
  2. Don't eat raw or undercooked meat, and wash all utensils, cutting boards, and prep surfaces thoroughly. This is especially important for lamb, pork, and beef.
  3. Wear gloves when gardening or handling soil, and cover any sandboxes. Be sure to wash your hands thoroughly after handling each.
  4. Don't drink unpasteurized milk.

Congenital Herpes Simplex

Herpes is a particularly common virus — the World Health Organization estimates that 3.7 billion people under age 50, nearly one-third of the globe's population, are infected. That being said, if you had herpes prior to getting pregnant, you're at a fairly low risk of transmitting that virus to your child, adds the WHO.

But if you contract the virus for the first time late in your pregnancy, particularly if it's in your genitals (so not orally), risk of transmission to the baby is much higher. (And remember, there's no vaccine or cure for herpes of any kind.) (

Congenital herpes simplex occurs in roughly 30 out of every 100,000 births, and most symptoms surface within the baby's first and second week of life, according to the Boston Children's Hospital. And as Dr. Harrison warns, the symptoms are serious. "[Congenital herpes simplex] in babies has devastating results, sometimes including death." She notes that babies are typically infected in the birth canal during delivery.

If you're pregnant, practicing safe sex is crucial in avoiding infection. Use condoms, and if you know someone with active symptoms associated with the virus (say, they have a physical outbreak on their genitals or mouth), wash your hands often around them. If an individual has a cold sore (which is also considered the herpes virus), refrain from kissing that person or sharing drinks. Last, if your partner has herpes, don't have sex if their symptoms are active. (More here: Everything You Need to Know About Herpes and How to Get Tested for It)


Although the term pandemic has recently become synonymous with the COVID-19 infection, back between 2015 and 2017, another super-dangerous epidemic was running rampant across the globe: the Zika virus. Similar to CMV, healthy adults typically don't develop symptoms when infected with the virus, and it tends to clear up on its own eventually, according to the WHO.

But when passed on to a baby through the uterus, it can cause serious complications, says Dr. Kroll. "[Zika] can cause microcephaly, or a small head, and other brain defects in newborns," he explains. "It can also cause congenital hydrocephalus [a buildup of fluid in the brain], chorioretinitis [inflammation of the choroid, the lining of the retina], and brain development issues." (

That said, transmission to the fetus when the mother is infected isn't a given. In pregnant people with an active Zika infection, there's a 5 to 10 percent chance the virus will be passed to their newborn, according to the CDC. A paper published in the New England Journal of Medicine noted that only 4 to 6 percent of those cases result in a microcephaly deformity.

Though that chance is minimal, and despite the fact that Zika was at a peak infection rate over five years ago, it helps to take precautions during pregnancy. Pregnant women should avoid traveling to countries that currently have Zika cases. And since the virus is primarily transmitted through an infected mosquito's bite, pregnant women should also stay cautious in tropical or subtropical regions (particularly where there are Zika cases), the WHO notes. Currently, there are no major outbreaks, despite isolated cases.

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