2,131. A Placenta Connected to a Fetus
Hilchos Issurei Biah 10:16
Let’s say that a woman expels something that resembles an animal or a bird and there’s a placenta connected to it. In such a case, we aren’t concerned that there might be another fetus; if it’s not connected, then we act stringently as if there were two fetuses. We consider the possibility that the fetus that was in the placenta might have worn away and the placenta of the fetus that looks like an animal might have worn away.
Hilchos Issurei Biah 10:17
In all cases of a placenta where we consider the possibility (of a fetus), the woman is not given pure days. Regarding a woman who expels something that doesn’t look like a human fetus or a fetus within 40 days of conception that hasn’t fully formed, if it was accompanied by blood, the woman is a niddah or a zavah; if it came out without blood, she remains ritually clean.