To the Editor: There is no such thing as a "partial birth abortion." But the Senate passed a bill purporting to ban it. (NY Times, March 14) The Senate bill is not about just "a procedure." It would ban a whole range of safe, medically approved abortion procedures that women need, including those that are most common during the second trimester. Nor does the bill make exceptions when a women's health is at serious risk. In reality, the Senate's so-called "partial birth abortion" ban would prevent doctors from doing what is best for their patients and would undermine women's health and erode their rights. Donna Lieberman Executive Director New York Civil Liberties Union