### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
My grandson is 4 months old Saturday and he has stopped sleeping. Fights it; and will not nap. He also is breastfed and has quit eating as much. About 1/2 what he was doing up until last week. They still swaddle him but that is not working. He is not as active nor talkative yet he has no other symptoms. Seems healthy, just these changes.

### output:

Hi, The usual amount of sleep for an infant your grandsons age is 9-12 hours at night plus 2-4 hours of nap time. Infant sleep behavior should be understood in the context of the relationship and interaction between infant and caregiver which impacts greatly on the quality and quantity of sleep.  How long has your grandson had trouble with sleeping? Temporary sleep disturbances that occur with acute illness usually are self-limited.  Certain factors are associated with chronic sleep problems such as inability to self-soothe, difficult temperament, maternal depression, and insecure maternal-infant attachment. How much is he crying? Vomiting? Does his diet consist of anything other than breast milk? What about babies environment? Noisy? Proper temperature? Smoking? Too bright? Does he sleep in his own bed? If he is not feeding as well at the breast as he used to, he could be losing weight. Should he be losing weight this is a situation that must be investigated immediately? I wish you were able to share more information with me.  However, in the USA, one of the well baby office visits with his pediatrician is at four months of age. Addendum: breast milk is not a good source of vitamin D. If he is not already taking this vitamin, he should have vitamin D daily. Hope I have answered your query. Let me know if I can assist you further.