1,083. Bleeding as a Consequence of Intimacy
156:1 If a woman saw blood because of marital relations - even not during relations but later on the same night - she is permitted to have relations again after she has purified herself. She must, however, prepare for the eventuality that it may happen again. If it happened on her mikvah night, then he must separate from her on her next mikvah night out of the concern that immersion followed by relations causes her to bleed and perhaps this will happen on the next mikvah night during relations. On the mikvah night after that, they need not separate because the main concern was because of immersion. Since she did not see blood on the second mikvah night, there is no longer any concern. Similarly, if she saw blood on the night after her immersion, they must separate on the night after immersion the following month, but not the month after that.
156:2 Since this woman developed a problem, even if she has a regular menstrual pattern, the next time she had relations, she must check herself for blood both before and after. This is to confirm that she did not see blood again as a result of marital relations. This woman should also consult a doctor immediately, especially if she saw blood during or immediately after marital relations, because if this happens to her three times in a row, it becomes a very difficult halachic situation.