Some infections during pregnancy cross the placenta and damage the fetal brain directly. Others trigger inflammation that does the harm without ever reaching the baby. Knowing which is which (and how to prevent them) is one of the most actionable parts of CP prevention.
Of all the prenatal factors that contribute to cerebral palsy, infections are arguably the most preventable. Vaccines, food safety, hand hygiene, and routine prenatal screening can prevent or catch most of the maternal infections that put fetal brain development at risk. This page covers which infections matter, how they cause CP, and what prevention looks like in practice. For the broader picture, see our overview of cerebral palsy causes or the umbrella guide on prenatal causes of CP.
The infections that contribute to CP fall into a fairly short list, but their mechanisms vary. Some attack the developing brain directly. Others damage it indirectly through inflammation. Some are vaccine-preventable; others require behavioral precautions. Sorting them out is the first step.
Infection is one of several environmental risk factors for CP, working alongside genetic predisposition, oxygen deprivation, premature birth, and maternal health conditions. Understanding how it fits into the broader picture helps explain why prevention strategies layer multiple approaches.
The exact contribution of maternal infections to CP risk is hard to pin down because infections often combine with other factors. A maternal infection can trigger preterm labor, raising risk through prematurity. It can compromise placental function, raising risk through oxygen deprivation. It can directly damage the fetal brain. The same infection might do any or all of these depending on timing, severity, and the host’s genetic background.
Genetic factors affect how vulnerable the developing brain is to infection-related insults. Two children exposed to the same maternal CMV infection may have very different outcomes depending on how their genes regulate inflammation, neuronal development, and tissue repair. This is why some children develop CP after seemingly mild prenatal infections while others come through significant infections unaffected. For the deeper picture of how genetics interacts with environmental factors, see genetic factors in cerebral palsy.
Maternal health and infection risk feed each other, which is why the two are hard to separate in the research.
Diabetes and obesity impair immune function, so infections are both more likely and more severe. Autoimmune conditions and the medications used to treat them change how the body answers an ordinary exposure. Smoking reduces ciliary clearance in the airway and blunts systemic immunity. Chronic kidney disease raises the risk of urinary tract infection during pregnancy, and untreated urinary infection is itself linked to preterm labor. Stress and sleep deprivation move the needle less, but they compound whatever else is going on.
Good prenatal management of underlying maternal conditions reduces infection risk indirectly, another reason routine prenatal care matters.
The infections most strongly linked to CP are clinically grouped as TORCH infections: an acronym capturing toxoplasmosis, “other” (a catch-all for syphilis, varicella, parvovirus, Zika, and others), rubella, cytomegalovirus, and herpes simplex. Bacterial infections of the membranes or placenta also matter.
These infections share a common feature: they can either reach the fetus directly or trigger maternal inflammation that does the harm without crossing. Modern prenatal care includes routine screening for several of them and prevention strategies for all.
The infections most strongly linked to cerebral palsy are a short list, and they do their damage by different routes.
Cytomegalovirus is the most common congenital infection in the United States, affecting roughly 1 in 200 newborns, and most maternal infections produce no symptoms at all, which is why it goes unnoticed. Rubella was once a leading cause of congenital disability and is now rare wherever vaccination is universal, though the MMR vaccine is live and has to be given before pregnancy rather than during it. Toxoplasmosis comes from undercooked meat, contaminated soil or cat feces and crosses the placenta, particularly when first acquired in pregnancy. Herpes simplex is usually transmitted during delivery, which is why cesarean is recommended when lesions are active. Varicella in pregnancy can cause congenital varicella syndrome, and vaccination beforehand prevents it. Zika is linked to microcephaly and severe neurological injury. Syphilis crosses the placenta, and routine screening catches it while penicillin still clears it. Group B streptococcus is a colonization rather than an illness, screened at 36 weeks and treated with antibiotics during labor. Listeria arrives through soft cheese, deli meat and raw seafood, and can cause fetal sepsis or meningitis. And chorioamnionitis, bacterial infection of the membranes, is the one with the clearest numbers attached.
Four mechanisms account for most of the damage, and only one of them requires the infection to reach the fetus at all.
Some infections invade fetal brain tissue directly: cytomegalovirus, rubella, toxoplasmosis and Zika. Others never reach the fetus and injure it anyway, because maternal cytokines cross the placenta and inflame tissue that is still being built. Inflammation damages the blood vessels feeding the developing brain. It disrupts neuronal migration during the windows when neurons are supposed to be arriving at their destinations. And it triggers preterm labor, which raises cerebral palsy risk on its own. That second pathway is what makes chorioamnionitis matter so much: a meta-analysis of the published cohorts found clinical chorioamnionitis associated with cerebral palsy at a relative risk of 1.9 in preterm infants and with cystic periventricular leukomalacia at 3.0. In full-term infants the association was stronger still, a relative risk of 4.7, though the confidence interval ran from 1.3 to 16.2 and the true figure could sit almost anywhere inside it.
The same infection in two different pregnancies can produce different outcomes depending on timing (first vs. third trimester), severity, maternal immune response, and fetal genetic background.
Standard prenatal screening in the United States covers HIV, syphilis and hepatitis B early in pregnancy, rubella immunity at the first visit, and group B strep at around 36 weeks, with targeted testing for cytomegalovirus, toxoplasmosis or Zika where symptoms or exposure warrant it.
Notice what is missing from that list. Cytomegalovirus, the most common congenital infection there is, is not screened for routinely in most of the country.
Most maternal infections linked to CP are preventable with established public-health tools: vaccines, screening, food safety, hygiene, and prompt treatment when infections do occur. The interventions are well-known and well-studied; the challenge is consistent implementation.
Prevention works best when it’s layered: combining vaccination before pregnancy, screening during prenatal care, safe behaviors throughout pregnancy, and prompt treatment of any infections that do develop. No single measure prevents everything; the combination prevents most.
Prenatal care contributes to infection prevention in a handful of concrete ways.
Immunity testing before pregnancy or at the first visit establishes status for rubella, varicella and hepatitis B. Where immunity is absent, MMR and varicella vaccination happens before conception, because both are live vaccines and cannot be given during pregnancy. Influenza vaccine can be given in any trimester, Tdap between 27 and 36 weeks, and COVID vaccination as currently recommended. Routine screening covers HIV, syphilis, hepatitis B and group B strep on the standard schedule. Targeted screening for cytomegalovirus or toxoplasmosis follows exposure history or symptoms. And a real conversation about food safety, hand hygiene and travel does more than any of the tests, because those are the exposures nobody screens for.
The practical steps with the highest impact are unglamorous and mostly free.
Hand hygiene around young children matters most, because the usual source of maternal cytomegalovirus is a toddler’s saliva. That is also why sharing food, cups and utensils with a small child is worth stopping during pregnancy, which is advice almost nobody receives. Cook meat thoroughly, against toxoplasmosis and listeria. Skip unpasteurized dairy and soft cheeses, listeria again. Wash produce, since toxoplasmosis travels on soil. Hand off the cat litter, or wear gloves and wash afterward. Use repellent and avoid travel where Zika is active. Take the recommended vaccines on schedule. And treat urinary tract infections promptly, because untreated ones raise the risk of preterm labor.
Beyond CP, maternal infections can produce a range of developmental, neurological, and sensory effects. Understanding the full picture of long-term outcomes helps families navigate post-birth surveillance and early intervention.
The same infection can produce different outcomes depending on timing and severity. CMV in early pregnancy may produce microcephaly, hearing loss, and CP; CMV later in pregnancy might produce only hearing loss or mild developmental differences. Knowing what to watch for guides post-birth follow-up.
Cerebral palsy is not the only outcome, and in many children it is not the most disabling one.
Microcephaly, a smaller than typical head circumference usually accompanied by brain underdevelopment, is strongly associated with Zika, cytomegalovirus and rubella. Sensorineural hearing loss is the one to watch: cytomegalovirus is the most common non-genetic cause of childhood hearing loss. Chorioretinitis and cataracts follow cytomegalovirus, rubella and toxoplasmosis. Seizures may appear in the newborn period or years later. Intellectual and learning differences range from subtle to substantial depending on when in gestation the infection landed. And some research reports elevated rates of autism after certain congenital infections. Many of these travel together, which is why a child diagnosed with cerebral palsy after a congenital infection needs hearing, vision and developmental screening rather than motor follow-up alone. Our page on non-motor symptoms of cerebral palsy covers what that screening looks for.
Many of these conditions co-occur with CP, which is why children diagnosed with CP often need broader screening for hearing, vision, and cognitive function. For more on this, see our guide on non-motor symptoms of cerebral palsy.
Several effects are not detectable at birth at all, which is the argument for long follow-up rather than a single clean newborn exam.
Cytomegalovirus-related hearing loss can appear or worsen across the first years of life even when the newborn hearing screen was normal. Some toxoplasmosis eye damage progresses through childhood. Learning differences usually surface at school age rather than before. Behavioral and emotional concerns often follow from the learning or sensory differences rather than standing alone. All of which adds up to ongoing surveillance of neurology, hearing, vision and development, not a discharge at twelve months.
Early identification of congenital infection (ideally in the newborn period) opens the door to interventions that improve long-term outcomes.
CMV is the most common congenital infection in the U.S. yet remains relatively unknown to the public. Most people who get CMV have no symptoms, but maternal CMV during pregnancy can cause hearing loss, vision problems, and CP in the child. Hand hygiene around young children is one of the most effective (and most underused) preventive measures available. Many states now mandate CMV screening for newborns; ask whether your hospital does.
Failure to screen for, recognize, or treat maternal infections during pregnancy can rise to medical malpractice when it leads to preventable injury. Common errors include missed STD screening, failure to vaccinate when indicated, missed urinary tract infections that progress to preterm labor, and untreated chorioamnionitis. Request a free case review.
Our nurse advocates can help you read your prenatal records and identify whether any infection-related concerns deserve a closer look. Get a free, confidential evaluation.
The TORCH group: toxoplasmosis, other infections including syphilis, varicella, parvovirus and Zika, rubella, cytomegalovirus and herpes simplex. Chorioamnionitis, a bacterial infection of the fetal membranes, belongs alongside them and carries the clearest evidence of the lot. A meta-analysis found clinical chorioamnionitis associated with cerebral palsy at a relative risk of 1.9 in preterm infants and 4.7 in full-term infants.
By two different routes. Some infections cross the placenta and infect fetal brain tissue directly, which is what cytomegalovirus, rubella, toxoplasmosis and Zika do. Others never reach the fetus and still cause harm, because maternal inflammatory cytokines cross the placenta, damage developing blood vessels, disrupt neuronal migration and trigger preterm labor. The second pathway is why an infection confined to the membranes can injure a brain.
They raise cerebral palsy risk, they cause other birth defects, and they increase the chance of preterm delivery, which carries its own risk. The specific harm depends on the organism. Untreated syphilis produces congenital syphilis; untreated group B strep colonization can produce neonatal sepsis; untreated urinary tract infection raises the odds of preterm labor.
First-trimester infections do the most structural damage, because that is when major brain structures are forming. Later infections tend to produce milder or more focal effects. The same organism in two pregnancies can produce very different outcomes for exactly this reason, which is why timing appears in every case description.
Vaccination before pregnancy for rubella and varicella, since both are live vaccines, plus influenza, Tdap and COVID vaccination during it. Routine screening on schedule. And the hygiene measures aimed at cytomegalovirus, which is the most common congenital infection in the country at roughly 1 in 200 newborns and the one least often discussed: hand washing around toddlers, and not sharing food, cups or utensils with them.
Yes. Smoking impairs maternal immune function and reduces placental blood flow at the same time, so an infection that a non-smoking pregnancy would clear can do more damage. Diabetes and obesity work similarly, raising both the likelihood and the severity of infection.
Kelsey is an experienced surgical nurse who works extensively with pediatric patients and families navigating birth injuries and cerebral palsy diagnoses. She is licensed by the Missouri Board of Nursing and operates under the Nurse Licensure Compact, allowing her to practice across compact-member states. As both a mentor and patient advocate, Kelsey focuses on safety, communication, and compassionate care: helping families understand medical procedures, treatment options, and the realities of pediatric conditions.
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