瑜伽論記 7.34

7.34

若唯依身心而轉等者，此中意難亦依孔穴業等而息得轉，非唯依身心，如在母腹中四位時無息義，故論言閉尸等位。

Regarding 'if it circulated relying only on body and mind', etc.: the meaning of the objection here is that breath can circulate also relying on apertures, karma, and so forth, and not relying only on body and mind; for instance, when in the four stages within the mother's womb, breath is absent, which is why the treatise speaks of stages such as the peśī.