From Chapter II of her 1920 book Woman and the New Race, she states the following:
So, too, with woman’s struggle for emancipation. Women in all lands and all ages have instinctively desired family limitation. Usually this desire has been laid to economic pressure. Frequently the pressure has existed, but the driving force behind woman’s aspiration toward freedom has lain deeper. It has asserted itself among the rich and among the poor, among the intelligent and the unintelligent. It has been manifested in such horrors as infanticide, child abandonment and abortion.
From Chapter X of the same:
While there are cases where even the law recognizes an abortion as justifiable if recommended by a physician, I assert that the hundreds of thousands of abortions performed in America each year are a disgrace to civilization.
She doesn’t stop there, though. In a speech to the Sixth International Neo-Malthusian and Birth Control Conference, she said the following:
In 1930, Pope Pius XII wrote his encyclical Castii Connubii, which reaffirmed the Roman Catholic Church’s prohibition of abortion. In 1931, Sanger wrote this in her response to the encyclical:
Human society must protect its children–yes, but prenatal care is most essential! The child-to-be, as yet not called into being, has rights no less imperative.
“The real alternative to birth control is abortion,” wrote Dean Inge, in his article already quoted. It is an alternative that I cannot too strongly condemn. Although abortion may be resorted to in order to save the life of the mother, the practice of it merely for limitation of offspring is dangerous and vicious. I bring up the subject here only because some ill-informed persons have the notion that when we speak of birth control we include abortion as a method. We certainly do not. Abortion destroys the already fertilized ovum or the embryo; contraception, as I have carefully explained, prevents the fertilizing of the ovum by keeping the male cells away. Thus it prevents the beginning of life.
In her 1938 autobiography, Sanger says the following on page 217:
To each group we explained simply what contraception was; that abortion was the wrong way—no matter how early it was performed it was taking life; that contraception was the better way, the safer way—it took a little time, a little trouble, but was well worth while in the long run, because life had not begun.