Thank you for your query. First of all, Congratulations on becoming the proud parents of a beautiful little girl. Would you please clarify a few things for me? 1) when she was pregnant, how many pus cells were there in the urine and was and infection confirmed by culture of their one before antibiotics were started? 2) when she had the fever after delivery, did she have any other symptoms like a cold, cough, any inflammation or pain at the episiotomy site( if she had one during a normal delivery) or at the incision site ( if I t was a c- section)? any burning or pain while urinating, and breast tenderness or inflammation? 3) does the fever still persist ? Ideally, if urine cultures were negative , she wouldn t need the antibiotics. however if the doctor suspected any lingering infection or any other source, they may asked her to continue for that purpose. Since she is having symptoms of gastritis ( inflammation in the stomach), it is better to stop the medication after discussing with her doctor. I recommend calling her doctor and reporting this issue so that she may advice you and alternative and medication to soothe her. Nitrofurantoin is generally safe while breastfeeding if the baby is being monitored for signs of anemia. it is passed through breast milk in small quantities. please discuss with your wife s doctor for alternatives and also with your daughters paediatrician. hope this helps. please get back to us if you have further questions . wish you all good health