One of the basic sources in the Talmud that deals with issues of birth control appears on our daf:
Rav Beivai taught a baraita before Rav Nahman. It is permitted for three women to engage in relations with a contraceptive resorbent [mokh]. These are they: A minor, and a pregnant woman, and a nursing woman. The baraita elaborates: A minor may do so lest she conceive and die; a pregnant woman, lest her existing fetus be crushed by another fetus and assume the shape of a sandal fish if she conceives a second time; and a nursing woman, lest she conceive, causing her milk to spoil, which will lead her to wean her son prematurely, endangering his health.
And the baraita further states: What is a minor girl? A minor girl is a girl from eleven years and one day old until twelve years and one day old. If she was less than that age or more than that age, she proceeds and engages in relations in her usual manner; this is the statement of Rabbi Meir. And the Rabbis say: Both this woman and that woman, i.e., in the cases of all these women, she proceeds and engages in relations in her usual manner, and from Heaven they will have mercy and prevent any mishap, due to the fact that it is stated: “The Lord preserves the simple” (Tehillim 116:6). Apparently a minor is unable to conceive.
The rishonim differ as to how to understand this baraita, and what its implications are for the halakha. According to Rashi, the discussion is whether a woman can insert a physical barrier into her vaginal canal as a means of birth control. Rabbi Meir’s position is that a woman who has reason to fear that pregnancy will result in danger to her or to her unborn child is permitted to do so, although it would be forbidden to other women. Tosafot and others reject Rashi’s explanation, arguing that inserting such a mokh during relations would be forbidden according to all opinions. They suggest that the mokh is an absorbent cloth that is inserted following sexual relations in an attempt to remove the semen. According to Rabbi Meir, a minor as well as a pregnant or nursing woman would be obligated to use this mokh in an attempt to keep a potentially dangerous pregnancy from developing (a method that today is recognized as being of limited use, if any), while other women would be permitted to do so.