This is a something many parents and doctors debate on. With or without CAH. I too worried and never let my daughter cry it out so I did some research on the crying it out method to the not crying it out method. I didn’t let her cry it out. She is 7 now. My opinion is this. I read somewhere that if an infant is crying there is a reason. You cannot spoil an infant by picking them up. Many debate it. I believe it. Call me crazy but to me it makes sense. Taking the CAH factor away, I still wouldn’t let any of my infants cry it out. That is their only way of communicating. It is their language. I believe there is no lesson the infant can learn by letting them cry it out. Again my own opinion don’t sue me. If they are crying they need something. Changing, food, or just plain comfort in their mother’s arms. Some call that comfort spoiling, I call it a real need. We all need our mother’s arms. My daughter was a light sleeper. Most of her problems were teething. The WORSE case of teething next to her father according to my mother in law. Whatever the case was, she was in need and I was there to comfort. It was what worked for me and my family. I am a firm believer in doing what works for you and your family. But to answer your question to the danger in letting them cry, I am not sure. I am sure it tires them out. I was told even when blood work is taken if they are too worked up it could alter the results a tad. (don’t quote me there) so I imagine in some way it does affect them. My daughter gets instant headaches when she cries today. So I really can’t answer that question from a medical point. I hope this helps. Sweet dreams!!!!! Congratulations on your new baby!!!!!