The Torah tells us about Sarah (Bereishis 11:30) “Vatehi Sarah akarah,
ein lah valad – Now Sarai was barren, she had no child.” The Gemara in Yevamos 64a-b learns from this verse that not only did Sarah not give birth, she did not have a “beis velad” (uterus) at all.
Bereishis Rabbah 53:5 and 63:5 says that Sarah did not have “ikar mitrin.”
This all seems to imply that Sarah did not have a uterus. But if that is the case, how could she have menstruated? Aside from the midrashim that she menstruated (e.g. Bava Metzia 87a), the Torah tells us (Bereishis 18:11) that Sarah had stopped menstruating due to her advanced age, clearly implying that when she was younger she had menstruated. (Cf. Rashi, Bereishis 18:8 that Sarah miraculously regained her menses.) Is this a midrash that contradicts science as we now understand it or can the two be somehow resolved?
R. Yitzhak Weiss (Minhas Yitzhak 1:125:6-7) says that we cannot bring a proof le-halakhah from Sarah because this midrash contradicts the physical reality as we know it. He then suggests that perhaps part but not all of Sarah’s uterus was damaged.
R. Ovadia Yosef in Yabia Omer vol. 3, Even Ha-Ezer 4:1 says about Sarah, “Therefore the text had to tell us that she did not have a ‘beis velad‘ – she did not have a ‘beis velad‘ at all.” This is in implicit disagreement with the Minhas Yitzhak.
Dr. Shaul Weinreb has suggested that “she did not have a uterus” is not meant literally but that she did not have a functioning uterus.
Dr. Josh Backon suggested that Sarah lacked eggs but had a uterus.
My rabbi, this past Shabbos, suggested that the midrash did not mean that Sarah literally had no uterus. It only meant that in shamayim it was decreed that she be incapable of giving birth.