I worked in secular Hospitals and Nursing Homes and Hospices. According to the Nursing Code (in my State, at least) a Nurse can refuse to assist in an abortion, and will be assigned to fill a place for another Nurse who will assist. However, if s/he works in surgery, they cannot refuse to assist in such things as Tubal Ligation (which sterilizes a woman); a sterilization procedure for a man; or a hysterectomy. Unless the hysterectomy or partial hysterectomy is done to treat some advanced cancer, it would go against the Church, as it also results in sterility. Done for serious disease state (such as life-threatening cancer) the sterility is a “secondary effect” of the required surgery to save a life, which would not be sinful. That’s why I worked after advanced training at a Catholic Hospital, then switched to Geriatrics and eventually Hospice, as I would not assist in abortions, or sterilizations. If you are in a specialty (such as pediatrics or medical wards for diseases), you can end up at least caring for patients having such procedures, including labor & delivery, which can involve tubal ligation. Working in the Nursery is usually not involved, but you can still be called in to assist in the Delivery Room. That’s why I switched specialties.