Some have argued an increase in autism-spectrum disorders is related to an increase in the rates of C-section surgery. When a patient has a C-section, the patient is in a hospital, in a setting where hospital acquired infections are common. C-section patients are given a course of broad-spectrum antibiotics, IV and orally, to avoid a hospital-acquired infection, arising from the surgery.

Researchers have reported a gut-brain connection in autism-spectrum disorders, and autistic children often have co-morbid gastrointestinal disease. C-section babies do not acquire necessary good bacteria from the birth canal; and the broad-spectrum antibiotics given to the mother before and after the C-section can reach the baby through the mother’s bloodstream and through breast milk, to alter the microbiome of the baby.