What is congenital CMV, and why is it particularly significant?

Cytomegalovirus, or CMV, is the most commonly transmitted viral infection passed from mother to baby during pregnancy, and it's a major cause of hearing loss, cognitive impairment, and cerebral palsy in infants. When a mother has never been infected before and catches CMV for the first time during pregnancy, roughly 30 to 40% of these primary infections transmit to the baby. Existing immunity from a past infection substantially lowers this risk, which is why avoiding a first-time infection during pregnancy specifically matters most.

How does someone actually catch CMV, and how can it be avoided during pregnancy?

CMV spreads through contact with bodily fluids, and young children, especially toddlers in daycare settings, are a common source since they often carry and shed the virus without appearing unwell. Practical prevention includes washing hands thoroughly after changing diapers or wiping a young child's nose or mouth, avoiding sharing food, drinks, or utensils with young children, and avoiding kissing a young child directly on the mouth during pregnancy specifically.

How can toxoplasmosis actually be avoided during pregnancy?

Cook meat thoroughly rather than eating it rare or undercooked, wash fruits and vegetables well before eating, and avoid unpasteurized dairy products. If there's a cat in the household, avoid handling the litter box during pregnancy if possible, or wear gloves and wash hands thoroughly immediately afterward if someone else can't do it. Wearing gloves while gardening and washing hands afterward is also a sensible precaution, since contaminated soil is another route of exposure.

Infections During Pregnancy That Can Cause Cerebral Palsy

Causes & Prevention 9 min read

Infections During Pregnancy That Can Cause Cerebral Palsy

Q: Why can an infection during pregnancy affect a baby's brain?

Infections can trigger the release of certain proteins called cytokines, part of the body's normal inflammatory response, which can circulate in the baby's developing brain and blood during pregnancy. This inflammatory response, rather than the infection directly attacking brain tissue in every case, is a key part of how some infections during pregnancy are linked to a higher risk of cerebral palsy.

Q: What is the surprising timing pattern with toxoplasmosis infection?

It runs in an almost counterintuitive direction. The chance of the infection actually transmitting from mother to baby is lower earlier in pregnancy and can reach as high as 90% very late in pregnancy. However, the severity works the opposite way: when transmission does happen early in pregnancy, the resulting effects on the baby tend to be considerably more serious than when transmission happens later. This is exactly why any suspected exposure early in pregnancy is worth discussing with a doctor promptly, even though the transmission risk itself is comparatively lower at that stage.

Q: Is rubella still a real risk if vaccines are widely available?

It's now far less common specifically because of widespread MMR (measles, mumps, rubella) vaccination, but it remains a real risk for anyone who isn't immune. Rubella infection during pregnancy can meaningfully raise the risk of cerebral palsy and miscarriage. Because the vaccine is a live vaccine and isn't given during pregnancy itself, checking immunity status and getting vaccinated beforehand, ideally before trying to conceive, is the key window for prevention.

Most infections during pregnancy come and go without lasting consequence. A small number don’t, and knowing which ones, how they actually spread, and what genuinely lowers the risk is some of the most practical prevention information available.

Written by CP Clinic Medical Team Tovmed Medical Center, Vinnytsia, Ukraine

Medically reviewed by Prof. Vigein Tovmasian PhD · Orthopedic Surgeon · Honorary Doctor of Ukraine

Why an infection can affect a baby’s brain

Infections trigger the release of certain proteins called cytokines, part of the body’s normal inflammatory response to fighting something off. During pregnancy, this inflammatory response can circulate in the baby’s developing brain and blood, not just the mother’s own system. This is a major reason some infections during pregnancy carry a real, documented link to a higher risk of cerebral palsy, separate from whether the infection reaches the baby’s brain tissue directly.

The three infections worth knowing

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Cytomegalovirus (CMV)

Most common

The most commonly transmitted viral infection passed from mother to baby during pregnancy, and a major cause of hearing loss, cognitive impairment, and cerebral palsy. Almost everyone is exposed to CMV at some point in life, so the real risk during pregnancy is specifically a first-time infection in someone who’s never had it before.

When that happens, roughly 30 to 40% of these primary infections transmit to the baby. Existing immunity from a past infection substantially lowers this risk. Young children, especially toddlers in daycare, are a common source since they often carry and shed the virus without looking unwell at all.

🐈

Toxoplasmosis

Second most common

Caused by a parasite most often picked up from undercooked meat, contaminated soil, or contact with cat feces. Newborns are frequently symptom-free at birth even when infected, but can be at risk for problems that show up later, including vision loss, which is exactly why follow-up monitoring matters even without obvious symptoms early on.

💉

Rubella (German measles)

Vaccine-preventable

Now far less common thanks to widespread MMR vaccination, but still a real risk for anyone who isn’t immune. Infection during pregnancy can raise the risk of cerebral palsy and miscarriage. Since the vaccine can’t be given during pregnancy itself, checking immunity and vaccinating beforehand is the key prevention window.

The surprising timing pattern with toxoplasmosis

Worth understanding clearly

This one runs almost backwards from what you’d expect. The chance the infection actually transmits from mother to baby is lower earlier in pregnancy, and can reach as high as 90% very late in pregnancy. But severity works the opposite way: when transmission does happen early on, the resulting effects tend to be considerably more serious than when it happens later. This is exactly why any suspected exposure early in pregnancy deserves a prompt conversation with a doctor, even though the transmission risk itself is comparatively lower at that stage.

What actually reduces the risk

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Cook meat thoroughly Avoid rare or undercooked meat, and wash fruits and vegetables well before eating them.
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Be thoughtful about cat litter Avoid handling the litter box during pregnancy if someone else can do it. If not, wear gloves and wash your hands thoroughly right afterward.
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Wash hands after contact with young children Especially after changing diapers or wiping a toddler’s nose or mouth, and avoid sharing food, drinks, or utensils with young children during pregnancy.
🌱
Wear gloves while gardening Contaminated soil is another route of exposure, so gloves plus handwashing afterward is a sensible precaution.
💉
Check rubella immunity before pregnancy, not during Since the vaccine isn’t given during pregnancy itself, this is a preconception step worth planning for directly.

If you develop a fever or other signs of infection during pregnancy, contact your healthcare provider promptly rather than waiting to see if it resolves on its own. Early evaluation genuinely widens the options available.

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Frequently asked questions

Why can an infection during pregnancy affect a baby’s brain?

Infections trigger cytokines, part of the normal inflammatory response, which can circulate in the baby’s developing brain and blood during pregnancy. This inflammatory response is a key part of how some infections are linked to higher CP risk.

What is congenital CMV, and why does it matter so much?

The most commonly transmitted viral infection passed to babies during pregnancy, and a major cause of hearing loss, cognitive impairment, and CP. A first-time maternal infection transmits to the baby roughly 30 to 40% of the time; existing immunity from a past infection substantially lowers this.

How does someone catch CMV, and how can it be avoided?

Through contact with bodily fluids, often from young children who shed the virus without appearing unwell. Prevention includes thorough handwashing after diaper changes or wiping a toddler’s face, and avoiding sharing food or utensils with young children during pregnancy.

What’s the surprising timing pattern with toxoplasmosis?

Transmission risk is lower earlier in pregnancy and can reach 90% late in pregnancy, but severity runs the opposite way: early transmission tends to cause more serious effects than later transmission. Any suspected early exposure is worth discussing with a doctor promptly regardless.

How can toxoplasmosis actually be avoided?

Cook meat thoroughly, wash produce well, avoid unpasteurized dairy, and be careful with cat litter, ideally having someone else handle it during pregnancy, or wearing gloves and washing hands thoroughly if not. Gardening gloves are a sensible precaution too.

Is rubella still a risk with vaccines widely available?

Far less common now, but still a real risk for anyone not immune. Since the vaccine isn’t given during pregnancy itself, checking immunity status and vaccinating beforehand, ideally before trying to conceive, is the key prevention window.

References

“Risk Factors for Cerebral Palsy.” Centers for Disease Control and Prevention (CDC). CDC ↗
“Toxoplasmosis, Cytomegalovirus, Listeriosis, and Preconception Care.” PMC. PMC ↗
“Congenital Toxoplasmosis: The State of the Art.” PMC. PMC ↗
Patel N, Chaudhari K, Patel DJ, et al. “TORCH Infection and the Enigma of Anomalous Fetal Development: Pregnancy Puzzles.” Cureus. PMC ↗

Medical disclaimer: This article is for informational purposes. Diagnosis, testing, and treatment decisions related to infections during pregnancy should be made with your obstetric care team directly.