You have to identify the exact cause. Association with childbirth may be a mere co-incidence. Your sleeping hours might not be matching with the baby's. Taking the help of a caretaker at home might help you to get a continous sound sleep. Family members support is also very necessary. Try to avoid nictine or caffeine containing products before retiring to bed. Try to go on to the bed only when you actually feel sleepy. If you are not getting sleepy within half an hour of going to, indulge in some activity like maybe reading a book.