I can support abortion to save the life of the mother. That doesnt mean I buy the position abortion is a moral good.
Its a necessary evil in strictly limited circumstances and should always be treated as such.
Forty years ago I heard a panel of international gynecology specialists --- Irish, Italian, Japanese and American-- agree that there is no disease that is caused by pregnancy, nor one that is cured by abortion.
My own gyn old me that, while dire circumstances might be encountered in some remote primitive clinic lacking blood and blood products for transfusions or antibiotics, nobody who is able and willing to practice modern obstetrics will ever encounter a situation in which abortion is a life-saving necessity.
Situations in which the baby is already irretrievably doomed (e.g. cancerous uterus, ectopic pregnancy) and which are treated by the removal of the mother's diseased organ, have never been morally, legally, or medically, classified as abortions. This was done without legal challenge even when abortion was prohibited throughout the United States.
So, no. Under U.S. legal precedent, at least, there is no reason to "write in" exceptions to the rule that you never directly, deliberately, with lethal intent, end the baby's life.