Likutei Moharan 135:5/ליקוטי מוהר"ן קל״ה:ה׳

15. Through this, the womb of a woman in labor is opened. As is brought in the Etz Chaim (Shaar 35:3): Just as there are tzirim (hinges) and d’latot (doors) to a house, so a woman has tzirim and D’LaTot (Bekhorot 45a). From the two DaLeTs, the shape of a closed- mem is made. This is where the fetus is formed. Study there.

2It is necessary to cut this mem into two dalets so that the fetus can come out. This is the meaning of va’yeshaseph : he cut it into four. He cut the mem into two dalets. Understand this (t his point about the “woman in labor” is explained elsewhere).