Tosfos "Vinimtzeis M'uberes" discusses whether a woman more than 3 months pregnant would show, based on the Gemorah later.
But wouldn't the woman know if she is pregnant, based on whether she gets her regular period? Do we need to explain that this is where we can't ask her, or she is not truthful? Why does Tosfos, and perhaps the Gemorah, seem to ignore the obvious --ask the woman if she had her period? Is there an issue to what extent we may rely upon her?
Avi Scheiner, Passaic, New Jersey, USA
Tosfos proves that the Mishnah (Yevamos 35b) must be talking about a woman that is in her first trimester because if she was farther on in her pregnancy and she was not showing then the Meyabem should not be held accountable for doing Yibum on a pregnant woman because there was no reason to suspect that she was pregnant since most women show after three months.
I think that what you are asking is that the Meyabem who does Yibum after three months (within the first three months he is Chayav under all circumstances as the Mishnah says) should still be held accountable because he could have asked her whether she had had her period recently and when she answered that she had not had it for three months, he should have suspected that she was pregnant even though she was not showing.
To answer that question I would ask the following question: if a woman has not had her period for three months and she is still not showing, would we assume that the cessation of her period is caused by pregnancy? Tosfos says that most women show after three months. Since there are other possible reasons for the cessation of the menstrual cycle such as extreme fright (YD 184:8) and illness, I'm not sure we would suspect that she is among the minority of women that do not show after three months. Furthermore, in Halachah, we do not find that cessation of the cycle is taken to be an indication of pregnancy.
In Hilchos Nidah (YD 189:34) we find that only once a woman is showing do we say that she no longer has to worry about her Veses Kavu'ah. It seems that cessation of a period was not taken by Chazal to be a clear indication of pregnancy. Rather the opposite is true: a clear indication of pregnancy is taken to be a sign of complete cessation of bleeding. The Shevet ha'Levi (vol. 3, #114) says that even if a woman does a pregnancy test and it is positive, we do not assume that her cycle has stopped and she still has to keep her Veses. The Meiri (Nidah 9a) says that, in fact, the cessation of bleeding is a result of the advanced development of the fetus, reached at the stage of Hukar Ubrah, and is similar to the cessation of bleeding in a woman that is sick.
Kol Tuv,
Yonason Sigler