Does Prolonged Pregnancy Increase Cerebral Palsy Cases?
A full-term pregnancy lasts about 40 weeks, but sometimes babies stay in the womb longer, leading to what doctors call a post-term or prolonged pregnancy, often after 42 weeks. Parents wonder if this extra time raises the risk of cerebral palsy, a condition that affects muscle control and movement due to brain damage early in life. The short answer is yes, prolonged pregnancy can increase the chances through certain complications, though it is not the most common cause.
Cerebral palsy often links to problems around birth, like lack of oxygen to the brain or infections. In prolonged pregnancies, the placenta, which delivers oxygen and nutrients to the baby, can start to wear out. This condition, known as placental insufficiency, means the placenta does not work as well. It can deprive the baby of what it needs, leading to low birth weight or even early delivery. These issues heighten the risk of brain injury that causes cerebral palsy. For example, if the placenta pulls away from the uterus wall too soon, called placental abruption, it cuts off the baby’s supply line and can lead to serious harm.[4]
Another worry is the umbilical cord. In overdue pregnancies, the cord might get compressed or tangled more easily because there is less fluid around the baby. This can cause birth asphyxia, where the baby does not get enough oxygen during labor. Oxygen shortages at birth are a known trigger for the brain damage seen in cerebral palsy cases.[4]
Most research points to preterm birth, or babies born too early before 37 weeks, as a bigger risk factor. Studies show that up to 15 percent of babies born between 24 and 27 weeks may develop cerebral palsy, far higher than in full-term or post-term cases.[1][4] Preterm infants face issues like brain bleeds or infections that damage developing brain tissue. But prolonged pregnancies still matter because they can force emergency deliveries that mimic some preterm risks.
Doctors watch overdue pregnancies closely with ultrasounds and tests to check the baby’s health. Inducing labor around 41 weeks is common to avoid these problems. While preterm birth dominates cerebral palsy statistics, avoiding both extremes, too early or too late, helps protect the brain.
Sources:
https://childrenscerebralpalsy.com/research-update-increased-prevalence-of-cerebral-palsy-in-extremely-preterm-infants/
https://www.bila.ca/does-aspirin-use-during-pregnancy-increase-the-risk-of-cerebral-palsy/
https://www.droracle.ai/articles/597766/how-can-a-pregnant-individual-with-cerebral-palsy-cp
https://www.nationalbirthinjurylaw.com/what-causes-cerebral-palsy
https://pmc.ncbi.nlm.nih.gov/articles/PMC12731818/
https://obgyn.onlinelibrary.wiley.com/doi/10.1002/pd.70049
