Can high fever during pregnancy cause developmental disorders? Yes, research shows that high or prolonged fevers in pregnant women can raise the risk of certain developmental issues in the baby, especially in the first trimester.[1][3][5] The main concern comes from fevers linked to infections, not the fever alone, but temperatures over 38.9 degrees Celsius or 102 degrees Fahrenheit that last 24 hours or more are a key threshold.[1]
Doctors define a risky fever as one reaching 38.9 degrees Celsius or higher for at least a day early in pregnancy. This level triples the chance of neural tube defects, like problems with the brain and spine forming properly.[1] Studies found that women with such fevers had babies with these defects at rates up to 5.9 percent, compared to zero in women without fever.[1] Other issues tied to first-trimester fevers include heart defects, cleft lip or palate, and even stillbirth.[1]
Fever can also link to neurodevelopmental disorders, such as autism or attention deficit hyperactivity disorder. Recurrent fevers might increase autism risk by up to 300 percent, especially with severe infections.[3] One review noted that maternal fever alone slightly raises autism odds, separate from any medicine used to treat it.[4][5] Untreated high fevers stress the fetus, raising its heart rate and leading to birth defects or developmental delays.[3][5]
The first three months are the most sensitive time because that’s when the baby’s organs and neural tube develop.[1] Fevers from flu, urinary infections, COVID-19, or viruses like cytomegalovirus can trigger this.[2] Cytomegalovirus, for example, causes fevers over 38 degrees Celsius and risks microcephaly or hearing loss if caught during pregnancy.[2] Parvovirus usually does not harm the baby, but it can cause fever and needs monitoring.[6]
Not every fever leads to problems. Mild ones under 39 degrees Celsius are less risky, and quick treatment with safe options like acetaminophen lowers the danger.[1][3] Experts stress treating fever promptly to protect both mother and baby, as infections behind the fever pose the real threat.[2][4] Always see a doctor for any fever over 37.8 degrees Celsius, especially with chills, pain, or breathing issues.[2]
Sources
https://www.droracle.ai/articles/621991/what-duration-of-hyperthermia-fever-is-considered-risky-during
https://www.tuasaude.com/en/fever-while-pregnant/
https://www.mississippifreepress.org/opinion-how-misleading-statements-on-acetaminophen-leave-expectant-parents-confused/
https://womenshealthresearchcluster.com/learn/womens-health-blog/what-the-science-really-says-about-tylenol-use-during-pregnancy/
https://www.acmt.net/news/acmt-position-statement-acmt-responds-to-the-acetaminophen-and-autism-controversy/
https://www.teamwmcn.nhs.uk/parvovirus-infection-in-pregnancy-/
