In Roe v. Wade the Supreme Court ruled that abortion may not be restricted at all in the first trimester. In the second trimester abortion may be regulated only for the mother’s health. After “viability,” abortion may be prohibited except where necessary to preserve the mother’s health. 
Roe’s companion case, Doe v. Bolton, defined maternal “health” as: “all factors - physical, emotional…, psychological, familial, and the woman’s age - relevant to the well-being of the patient.”
Thus, abortion is legal — and cannot be prohibited — in the 7th, 8th, or 9th months of pregnancy if any of these reasons is invoked.
“[N]o significant legal barriers of any kind whatsoever exist today in the United States for a woman to obtain an abortion for any reason during any stage of her pregnancy.”