Hi,
Welcome to the ehealthforum and I am really glad to help you out. Your concern is regarding the loss of libido/sexdrive after childbirth. This lack of sex drive can be due to hormonal changes that occur in the body during this time or the psychological trauma of child birth.
It can also be due to anemia, overacyive pituitary gland causing hyperprolactinaemia or abnormalities in the production of luteinising hormone (LH). My sincere advice is to consult a gynecologist and get these possibilities ruled out. Psychological sessions of both the partners also help.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care.