7month old baby just finished antibiotics for uri and is still coughing...why?

Virus?: Most uri's are caused by viruses, not bacteria, so antibiotics will not be effective (unless a specific bacteria was found). The cough from a virus can last up to two weeks. If they are slowing getting better during this time period, that is good. If they appear to be worsening, are having trouble breathing, or seem like they are getting dehydrated (less wet diapers), they need to be reevaluated.

Inflammation/cough: After a viral infection, there can be prolonged inflammation in the airways underlying the persistent cough. Your doctor will check the baby for wheezing and/or signs of pneumonia or an ear infection. Continue to keep the baby well fed, hydrated and monitor for any fever. If the cough has lasted more than 3 weeks, a visit with your M.D. Is indicated.

Persistent cough: It is very common for a cough to last for a few weeks after a cold. As long as your child is eating, drinking and generally acting normally there is nothing to worry about.