נדה א׳:ד׳ - א׳:ה׳

משיוודע עוברה – at the end of three months from the day that she became pregnant.

עד שתגמול – until will be completed for her son twenty-four months (i.e., two years). And even if he died within twenty-four months, sufficient for her is her time, for the woman who gives birth (and has been in confinement), her limbs are loose/shaky and her full strength (literally, “her blood”) doesn’t return until after twenty-four mouths (see Talmud Niddah 9a). But from then and onward, behold she is like all the women and becomes defiled in the time of twenty-four astronomical hours or from one examination to a previous examination, and even though she is continually nursing four or five years.

וגמלתו או מת ר' מאיר אומר מטמאה מפקידה לפקידה – for he (i.e., Rabbi Meir) holds that blood is disturbed (i.e., decomposed) and turns into milk (see Talmud Niddah 9a). But when she is not nursing, even prior to twenty-four months, the blood returns to its place and returns to be menstruating.

כל שעברו עליה שלש עונות – an intermediate-size period is thirty days. And since that these three intermediate-sized periods have gone by for her following her arrival at being close to old age, sufficient for her is her time. And she is called being close to old age, for all who call her: “Mommy, Mommy,” on account of her old age but she does mind.

כל אשה – [every woman] and even one who is not old and for whom three periods have passed and she did not see it (i.e., a drop of blood), sufficient for her is her time.

מעוברת ומניק שעברו עליהן שלש עונות – but not if for whom they have not passed, for it is not like the first Tanna/teacher who said (see Mishnah 4): “Once it is known that the fetus is present,” and a nursing mother once he has been born. But the Halakha is not according to Rabbi Eliezer nor according to Rabbi Yossi.