As it stands the opinions of people who have zero involvement in a woman's reproductive cycle easily exert legislative and legal control over the options available to women.
Can you provide even a single instance of male reproductive regulation subjected to similar legislative control?
> In fact, as it stands now, the options available to women are vastly superior
You think of abortion as a form of birth control because your involvement in the process is essentially binary. Either you want a child or you don't. Either you wear a condom or you don't. For women exercising control over their reproductive rights isn't restricted to the timespan of a sexual encounter. An association between birth control and abortion in the greater context of reproductive rights seems to me indicative of a singular and fairly rigid perspective.
> The fact that only women can bear children does not make the regulation of abortion "discrimination".
Perhaps you should study the definition of discrimination. My OED lists two definitions to include: "the unjust or prejudicial treatment of different categories of people or things, especially on the grounds of race, age, or sex" and "recognition and understanding of the difference between one thing and another". In its most neutral definition, that is in the sense of differentiating two things, discrimination is rendered necessary by laws regulating abortion specifically as a direct result of the fact that women are the only ones who can become pregnant. The definition with more negative connotations makes reference to prejudice. The Wizards of Ox define prejudice as "preconceived opinion that is not based on reason or actual experience", or alternatively "harm or injury that results or may result from some action or judgment". Give that anti-abortion laws are passed, in part, by men whom by definition have no actual experience with the subject of legislation, it doesn't seem much of a leap to interpret such behavior as being prejudicial and thus discriminatory.
> Do you think that abortion on the day before birth should be legal?
In some cases, absolutely. Consider a premature baby born five months before it should be with no hope to survive, or the case of last minute complications that threaten a woman's life, or last minute discovery of terminal congenital defects.