What Causes Cerebral Palsy During Pregnancy: Understanding Risk

Cerebral palsy (CP) is a condition that affects how a person moves and controls their muscles, and it actually affects way more kids than most people realize—about 1 in every 345 in the U.S. And here’s a twist: most cases don’t even start during birth. Nope—up to 85% begin before a baby is born, while they’re still chilling in the womb.

Understanding Cerebral Palsy and Brain Development

Cerebral palsy is really just a name for a bunch of movement and balance problems that happen because the brain didn’t develop the way it was supposed to. Think of the brain like a super complicated computer that’s being built from scratch during pregnancy—wires going everywhere, systems starting up, the whole deal.

If something interrupts that building process—like an infection, lack of oxygen, or even genetic glitches—the “hardware” for movement can get affected. Most of the major brain-building happens in the second and third trimester, which is why problems during that time can have a bigger impact. It’s kind of like trying to update your phone during the final 2% of installation—if something goes wrong then, the whole system might glitch.

Maternal Infections: A Leading Prenatal Risk Factor

Infections during pregnancy are one of the biggest reasons a baby might develop cerebral palsy. If a mom gets certain viruses or bacteria, her body’s “fight mode” can actually affect the baby’s developing brain.

High-risk infections include:

Rubella (German measles): Imagine getting a virus that seems harmless but, during early pregnancy, can seriously interfere with how a baby’s brain grows.
Cytomegalovirus (CMV): This one is sneaky—super common and often invisible. But if it hits during pregnancy, it can cause lasting brain and development problems.
Toxoplasmosis: Yes, the thing everyone warns pregnant people about when it comes to cat litter. Also found in undercooked meat.
Herpes simplex virus: Both HSV-1 and HSV-2 can pose risks if they reach the fetus during pregnancy.
Bacterial infections: Things like chorioamnionitis (an infection around the baby) can spark intense inflammation that affects brain development.

Researchers writing in the Journal of Pediatrics say it’s often the inflammation, not the germ itself, that causes trouble. Think of it like setting off a smoke alarm while cooking—sometimes the alarm does more to wake the house than the tiny bit of smoke ever would.

Oxygen Deprivation and Blood Flow Issues

Your brain—my brain—everyone’s brain runs on oxygen like a phone runs on battery. For a developing baby, that oxygen is absolutely everything. When the brain doesn’t get enough of it (called hypoxia), or none at all (anoxia), brain cells can get damaged or develop in the wrong way, which can lead to cerebral palsy. Think of it like trying to build a Lego castle in the dark—you’re going to end up with missing pieces and weird shapes.

Prenatal causes of oxygen deprivation include:

Placental complications: If the placenta detaches too early (placental abruption) or blocks the exit (placenta previa), the oxygen “delivery system” gets interrupted.
Umbilical cord problems: If the cord gets squeezed, twisted, or drops into the birth canal too early, it’s like stepping on a garden hose—the flow slows or stops.
Maternal cardiovascular conditions: High blood pressure, preeclampsia, or heart problems can weaken blood flow to the placenta.
Severe maternal anemia: When the mom’s iron levels are super low, her blood can’t carry enough oxygen—kind of like trying to deliver mail with half the mail trucks missing.
Blood clotting disorders: These can affect how blood moves through the placenta or even cause a fetal stroke, which can interrupt normal brain development.

Researchers writing in the American Journal of Obstetrics and Gynecology say something surprising: long-term, low-level oxygen issues during pregnancy may actually cause more risk than those dramatic, sudden oxygen drops you hear about during labor.

Multiple Pregnancies and Premature Birth

Twins, triplets, and those rare “I-saw-this-on-a-documentary” multiples come with a much higher risk of cerebral palsy. In fact, twins have about four times the risk compared to single babies, and triplets face even more challenges. It’s not because anything is “wrong” with them—it’s just that growing more than one baby at a time is a serious high-level challenge for the body.

Why multiple pregnancies increase risk:

Premature birth: Multiples are usually born early—sometimes way early—and prematurity is one of the biggest risk factors for CP.
Low birth weight: Babies in multiple pregnancies tend to be smaller, and lower weight is strongly linked to higher CP risk.
Twin-to-twin transfusion syndrome: When identical twins share a placenta, sometimes one gets more blood than the other.
Death of a co-twin: If one twin passes away in the womb, the surviving twin may face sudden blood pressure changes or clotting issues that can harm brain development.

Babies born before 32 weeks are especially vulnerable—about 1–2% of very premature babies develop CP, compared to only 0.1–0.2% of full-term babies. In other words, being born early doesn’t just mean wearing tiny diapers—it means the brain is still finishing some of its most important work.

Maternal Health Conditions and Lifestyle Factors

A bunch of different health issues and lifestyle choices during pregnancy can raise the chances of a baby developing cerebral palsy. But let me say this loud and clear: none of these guarantee CP will happen. They just tilt the odds a little—not destiny, just risk.

Maternal Health Conditions Associated With Increased Risk:

Thyroid disorders: If the thyroid is running too fast or too slow, it can throw off the hormones the baby’s brain needs.
Diabetes: Both regular diabetes and the kind that shows up during pregnancy can increase CP risk—especially if blood sugar isn’t well controlled.
Seizure disorders: Moms with epilepsy have a slightly higher risk, partly because seizures and some anti-seizure meds can affect fetal development.
Autoimmune disorders: Conditions like lupus can create inflammation that messes with how well the placenta works, kind of like static on a phone line between mom and baby.

Lifestyle Factors That May Increase Risk:

Substance use: Alcohol, cigarettes, and drugs during pregnancy can all affect how the baby’s brain grows.
Exposure to toxins: Things like lead, mercury, or harsh chemicals? Big no. Babies’ brains are way too sensitive for that.
Inadequate prenatal care: Skipping prenatal checkups is like ignoring the warning lights on a car dashboard. Issues that could’ve been caught early may get missed entirely.

Genetic and Chromosomal Factors

Cerebral palsy isn’t usually a “genetic disorder” in the way people think—but genetics can still play a behind-the-scenes role. Sometimes, certain genes or chromosomal quirks make a baby’s brain more vulnerable, like having a phone with a screen that cracks a little easier than others.

Genetic considerations include:

Chromosomal abnormalities: Some genetic syndromes come with both learning differences and movement challenges that can look a lot like CP.
Gene mutations: Scientists have found specific genes that, when they glitch, make babies more likely to develop brain injuries like periventricular leukomalacia (PVL).
Familial patterns: CP-related brain vulnerabilities seem to run in families—kind of like how some families all have the same laugh or the same weird ability to wiggle their ears.

Even with all this, most CP cases still come from things that happen during pregnancy—not the DNA itself. Research is growing fast, but environment is still the main player.

Blood Incompatibility and Jaundice

Now here’s a wild one: something as simple as blood type differences can actually be risky. When a mother and baby have incompatible blood types—especially Rh or ABO types—it can cause severe jaundice. Not the mild “baby looks a little yellow” kind, but the dangerous kind called kernicterus, where extra bilirubin builds up and harms the brain.

Thanks to modern prenatal care (and superhero-level inventions like RhoGAM shots), this problem is way rarer today. But if blood incompatibility goes unnoticed or untreated, it can still lead to brain damage and increase the risk of cerebral palsy.

Stroke and Bleeding in the Fetal Brain

Yes, babies can actually have strokes before they’re even born — and those strokes can lead to cerebral palsy. A fetal stroke basically means something disrupted blood flow in the developing brain, either through bleeding (a hemorrhagic stroke) or a blockage (an ischemic stroke). It sounds dramatic because… well, it is.

These strokes may result from:

Maternal blood clotting disorders
Placental blood clots that break free and travel to the baby’s brain
Abnormal blood vessels in the fetus
Trauma to the mother’s abdomen — think serious accidents, not bumping into a table
Severe maternal infections that stir up inflammation

There’s also something called periventricular hemorrhage — bleeding around the brain’s fluid-filled spaces. Premature babies are especially vulnerable here. When this area gets damaged, the brain’s “white matter highways,” which help control movement, can be affected, increasing CP risk.

Prevention Strategies and Risk Reduction

We can’t prevent every case of cerebral palsy — biology can be unpredictable — but understanding the risks gives families and doctors a fighting chance. Think of it like knowing all the potholes on a road trip so you can avoid blowing a tire.

Recommended prevention measures include:

Comprehensive prenatal care: Regular checkups help doctors catch problems early, before they snowball.
Vaccination: Making sure you’re protected from rubella and other infections before pregnancy is huge.
Infection prevention: Good food safety, washing your hands, and staying away from sick people really does matter.
Management of chronic conditions: Keeping diabetes, thyroid issues, and other conditions under control protects the baby’s development.
Avoiding harmful substances: Alcohol, cigarettes, and drugs can seriously derail brain development — a hard no during pregnancy.
Appropriate medication management: Always double-check meds with a doctor to make sure they’re safe.
Monitoring multiple pregnancies: Twins, triplets, etc. need extra attention to stay safe.
Healthy lifestyle: Good nutrition, healthy weight gain, and safe exercise help support the baby’s brain from day one.

When to Seek Medical Attention

If someone is pregnant, there are certain signs that mean “don’t wait, get checked now.” These symptoms can hint that something is going on that might affect the baby’s brain development — and catching problems early can make a huge difference.

Pregnant women should seek immediate medical attention if they experience:

Signs of infection like fever, chills, or unusual discharge
Decreased fetal movement — basically, if the baby suddenly seems way quieter than usual
Vaginal bleeding or leaking fluid
Severe or persistent headaches
Vision changes or major swelling (possible signs of preeclampsia — a serious condition)
Severe abdominal pain
Constant vomiting that won’t let up

Getting help fast can sometimes prevent the kinds of brain injuries that lead to cerebral palsy. Think of it like calling a mechanic as soon as your car starts making that weird humming sound — waiting usually makes things worse.

The Importance of Early Diagnosis and Intervention

Even though this article talks a lot about what causes CP before birth, what happens after birth matters just as much. The earlier a child gets diagnosed and supported, the better their chances of reaching their full potential.

Parents who know there were complications during pregnancy should talk to their pediatrician about keeping a close eye on development. It’s not about being scared — it’s about being prepared.

Early intervention services — like physical therapy, occupational therapy, and speech therapy — can be total game changers. They help kids build skills, strengthen muscles, and gain independence, whether their CP is mild, moderate, or severe. It’s basically giving the child the tools they need as early as possible so they can thrive.

Conclusion: Knowledge Empowers Prevention and Preparation

Knowing what causes cerebral palsy during pregnancy gives parents and doctors a huge advantage. Most CP starts before birth, but many of the risks — like infections, oxygen problems, or unmanaged health conditions — can be spotted and handled early with good prenatal care.But here’s the truth: even if a mom does everything right, CP can still happen. Biology isn’t a perfect machine, and parents should never blame themselves. Sometimes life throws curveballs no one can dodge.