Hi, Thanks for posting in HCM. I understand your concern. Use of heating pad and taking hot bath during pregnancy for relief of pain wouldn t affect the baby as it is more of a localised treatment. But, it would be advisable to avoid it too frequently during the later months of pregnancy as heat may induce contractions. It would be better if she uses pain relieving gels for topical application in case she has pains. Hope the information provided would be helpful. All the best.