TT #691 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:06
And it shall be that the firstborn that she bears shall succeed to the name of his dead brother, so that his name shall not be blotted out from Israel.
Torah Temimah points to Yevamot 24a.
TT lemma: אֲשֶׁר תֵּלֵד.
אֲשֶׁר תֵּלֵד – פְּרָט לְאַיְלוֹנִית שֶׁאֵינָהּ יוֹלֶדֶת.
English: “That she bears” — excluding an aylonit (a woman who cannot bear children).
On the daf / in context: Even though the main derashah of “the firstborn” is applied to the yavam, the language “that she bears” is also used to exclude a woman incapable of childbirth from the laws of yibbum and chalitzah.
Mi’ut excluding the aylonit.
An aylonit is exempt from yibbum and chalitzah; the act has no legal effect for her.