Chullin 71: Ritual Impurity of a Fetus that is not Alive

A new Mishna teaches about women and ritual impurity.  How does her status change if her fetus dies while still in utero?  If she reaches and touches the dead fetus in her womb, the she contracts ritual defilement due to contact with the dead.  However, she reminds ritually pure until the fetus has been delivered.

The Gemara argues that a dead fetus does not defile other objects/people because it is tumah beluah, encapsulated defilement.  The midwife who contracts ritual defilement does so according to rabbinic but not by Torah law.  After the head has been delivered, the rabbis and the midwife disagrees regarding whether or not the fetus is capable of defilement.  

The mother does not ritually defile because of tumah beluah.  The Sages offer many opinions regarding this ruling.  Rashi says that the fetus is as if it is fully digested and so it can't defile anything else.  In Masechet Nidda, Rashi teaches that when defilement is encapsulated in an animal, it is as if it has disintegrated.  Touching and carrying do not spread ritual impurity.  The Meiri and others says that the fetus is given minor status within the host animal.  Rumba says that encapsulated impurities are enveloped by the body which acts as a chatzitza, separation that block the defiled object from others (like a cover on an earthenware vessel.