Smelly urine is otherwose asymptomatic baby is most commonly due to dehydrations and second cause wuld be urinary tract infection. For this i wuld require more history regarding frequency and if urination is painfull. But in both the cases one intervention wuld help that is increasing oral fluid intake in form of water, lime water juice etc.
Next Steps
if this continues and becomes symtomatic i wuld recomend a urine examination and further evaluation.
Health Tips
watch for fever and dehydration.