Given the data you provided (8 month old baby defecates hard balls sometimes and does not want to defecate on its own), your baby might be experiencing constipation. Constipation is difficulty in passing a stool or less frequent defecation. The feces might be small and hard or it can be of regular size but still hard to pass.


Constipation is often seen in infants. It might be a transitory condition. In formula fed infants the constipation might be related to soy formulas. Replacing them with extensively hydrolyzed casein formulas might be helpful.


It is important to recognize whether the passage is really constipation. If the defecation is accompanied with pain and the child sometimes avoids or delays defecation, then constipation might be present. Straining while defecating does not necessarily mean that there is a constipation. Infants have weak abdominal muscles and straining helps them with defecation. If a soft stool comes out within several minutes of straining then there is no constipation.


You might want to visit the pediatrician of your baby to check whether the condition is transitory or there is a medical condition affecting the defecation that needs to be treated.