TT #11 · Parashas Toldos · Passuk 25:24
When her time to give birth was at hand, there were twins in her womb.
Torah Temimah points to Berachos 5b. E-Daf · Sefaria — Berachos 5b
Whoever places his bed between north and south — his wife will not miscarry… linked to “and her days were filled to give birth.”
Custom (Bavli — bed orientation and full-term birth)
Orienting the marital bed between north and south is associated with a full-term pregnancy.