Wonders of Pregnancy

Another example: when a person places his things on the pan of a balance scale, as the weight increases with addition of each new object, the pan descends further. Whereas with God, the opposite occurs: As the fetus that He placed in the womb gets heavier, it ascends to a higher chamber in the womb. Rashi explains (note 28) that the first 3 months the fetus resides in the lower chamber of the womb; the next 3 months in the middle chamber and the final 3 months it moves up to the highes chamber of the womb.