Hello, I have gone through your query and understood the concern. I would also like to know if your daughter-in-law had an induced vaginal delivery, a a preterm spontaneous delivery or an abdominal delivery. The possible reasons for the fever are breast engorgement, infection in the sutures, infection of the uterus, systemic infections, dehydration, urinary tract infections and so on. A proper appraisal of the situation is to be done by the specialist attending on her before she is sent home. Swabs should be taken, blood counts and urinalysis performed and if necessary culture tests should be done apart from maintaining fluid and electrolyte balance. Breast conditions should also be treated appropriately. Hope you find this information useful. Take care.