Niddah 27 - Afterbirth That Came Later
After Rav's death, his student Rav Yehudah and his other students went to study with Shmuel, and were telling him the statements of Rav. Rav Yehudah said, "For the first three days after the birth of a child, the emergence of an afterbirth is attributed to that child that was born. There is no concern for another child that might have dissolved, and no ritual impurity associated with it - nor any special laws for the woman. After three days, we must be concerned with the possibility that there was another child.
However, as the other students of Rav added, that's only if she first had a miscarriage, and then the afterbirth, and not the other way around. This is also only true when the first child was sufficiently developed that had it been a full-term baby, it could have survived. Since Rav Yehudah did not relate these details accurately, Shmuel looked at him with displeasure. Besides, sometimes even an afterbirth that comes up to twenty three days after a miscarriage may be still attributed to it.
Rabbi Yose ben Shaul asked, "If a woman aborts a fetus in the shape of a raven, and an afterbirth after that, do we attribute the afterbirth to the raven-shaped fetus? Rabbi Yehudah the Prince answered, "No, since ravens don't have afterbirth, we do not attribute it." Rabbi Yose continued, "But what if the afterbirth is attached to it?" Rabbi Yehudah said, "It is impossible." However, he was proven wrong by a teaching that considered just such a case.
Art: George Stubbs - The Farmers Wife and the Raven