My daughter had her 4 month check up today and in 4 weeks she only gained 4oz. She was 10lbs 10oz and she's now 10lbs 14oz. She has great wet diapers and nurses all the time. I thought she would've gained more than just 4oz. Her pediatrician wasn't concerned but I am, she is in the 10th percentile for height and weight. When she was 2 months old she was in the 25th percentile. Am I doing something wrong?