Drow mothers, and especially MatronMothers, rarely have the time or inclination to take care of their children themselves. Those who can leave this chore to some dependent female, usually one of their own daughters. Still, this can be risky, as the WeanMother has a great deal of influence over the developing child. It is safest to only leave your children in the hands of someone utterly dependent on you. Thus, any particular drow girl is rarely wean mother more than a few times, and it is considered something of a rite of passage.
The Weaning Order of House Nemalzhi
MatronNemalzhi weaned Zarathustriel and Zhe'raen herself. She has also recently taken up the task of weaning LuaXena, Xunice, and JhulTana - a fact that can be seen as a gesture of both respect and lack of trust for her own daughters.
Zarathustriel weaned Zhaunil and Ahriman
Zhaunil weaned Xoroastria
Xoroastria weaned Nirl
As fourthboy, Velve did not merit noble weaning, and was raised by the household.