Abortion should not be considered unethical during any stage of pregnancy. For many women, their menstrual cycles are irregular, causing them to not realize how far along they may be in their pregnancy. Women often don't find out they are pregnant until much later in their pregnancy, even after the first trimester. All pregnancies are different, and some women won't experience any pregnancy symptoms until much later. The common 12 week cut-off for when an abortion can be carried out is too short of a time frame, since a woman doesn't always know until it is considered “too late”.
Women get abortions for many different reasons. These reasons include rape or incest, making it unethical for the woman to be forced to have a baby she does not want, or one that was conceived under traumatic experiences. Another factor can be financial issues. Abortions are not free, and there are instances where a woman cannot always meet the cost of having an abortion right away. Whatever the reason may be, a woman has a right to chose whether or not she wants to have a baby, and should be able to get an abortion at any stage in the pregnancy.