If a woman’s yom haveset falls at night how many and when should she do (a) bedikah(os)?
What about if the veset is during the day?
If the yom haveset falls at night, she should do one bedikah, before she goes to sleep. If during the day, one bedikah is sufficient (during the day), but several poskim mention that it is preferable to do more. Others write that a bedikah should be done after the onah, but this has not been rules by most authorities.
Yoreh De’ah 184: Sidrei Taharah; Chavas Daas 22; Shulchan Aruch Harav 28; Bach and Perishah 18; Chochmas Adam 108:9 and 189:4; concerning the number of bedikos, see Iggros Moshe, Yoreh De’ah 3:48; Chazon Ish 80 (end).