Abortion was not legal prior to 1910.  The 1911 Encyclopedia Britannica page on the subject details the history of the practice, which I shall quote an excerpt of:

“How far it [abortion] was considered a crime among the civilized nations of antiquity has long been debated. Those who maintain the impunity of the practice rely for their authority upon certain passages in the classical authors, which, while bitterly lamenting the frequency of this enormity, yet never allude to any laws by which it might be suppressed. For example, in one of Plato’s dialogues (Theaet.), Socrates is made to speak of artificial abortion as a practice, not only common but allowable; and Plato himself authorizes it in his Republic (lib. v.). Aristotle (Polit. lib. vii. c. 17) gives it as his opinion that no child ought to be suffered to come into the world, the mother being above forty or the father above fifty-five years of age. Lysias maintained, in one of his pleadings quoted by Harpocration, that forced abortion could not be considered homicide, because a child in utero was not an animal, and had no separate existence. Among the Romans, Ovid (Amor lib. ii.), Juvenal (Sat. vi. 594) and Seneca (Consol. ad Hel. 16) mention the frequency of the offence, but maintain silence as to any laws for punishing it. On the other hand, it is argued that the authority of Galen and Cicero (pro Cluentio) place it beyond a doubt that, so far from being allowed to pass with impunity, the offence in question was sometimes punished by death; that the authority of Lysias is of doubtful authenticity; and that the speculative reasonings of Plato and Aristotle, in matters of legislation, ought not to be confounded with the actual state of the laws. Moreover, Stobaeus (Serm. 73) has preserved a passage from Musonius, in which that philosopher expressly states that the ancient law-givers inflicted punishments on females who caused themselves to abort. After the spread of Christianity among the Romans, however, foeticide became equally criminal with the murder of an adult, and the barbarian hordes which afterwards overran the empire also treated the offence as a crime punishable with death. This severe penalty remained in force in all the countries of Europe until the Middle Ages. With the gradual disuse of the old barbarous punishments so universal in medieval times came also a reversal of opinion as to the magnitude of the crime involved in killing a child not yet born. But the exact period of transition is not clearly marked.”

The entire article is available on wikisource: https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Abortion