How Can Nails Harm a Pregnant Woman?

Kobi asks: "Does Jewish law really prohibit throwing nails on the ground because they might cause a pregnant woman to miscarry? And if so, is this a Kabbalistic idea or a realistic claim?"

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The source for this topic is found in the Talmud (Moed Katan, page 18a). It tells of Rabbi Yochanan, who was in the study hall on a weekday of the intermediate days of a festival, trimming his nails and throwing them on the floor to teach his students certain laws. The Talmud questions this, noting that the righteous bury their nails, the pious burn them, and the wicked throw them on the ground because a woman might encounter them and miscarry as a result. The Talmud responds that women are not found in the study hall, so Rabbi Yochanan didn’t worry about throwing his nails on the floor. As we see, our sages did not say that nails are impure (since Rabbi Yochanan threw them in the study hall).

This practice is not mentioned in the Shulchan Aruch, but the Kitzur Shulchan Aruch and later authorities like the Mishnah Berurah (Orach Chaim, Siman 260, Siman Katan 6) and Ben Ish Chai (Second Year, Parasha Lech Lecha, Ot 14) quote this Talmud and elaborate on what should be done to prevent this harm. Therefore, to this day, we are careful to dispose of clipped nails properly.

The commentators offered two explanations for this practice—one natural and one mystical. The natural explanation is quite understandable, as it is known and accepted that pregnant women can miscarry due to the smallest matters, given that their psychological and emotional state determines the wellbeing of the fetus, especially in its early stages (hence a pregnant woman who suddenly craves something sweet should have her request fulfilled immediately). Here is an important fact on this topic:

"Reasons for miscarriage: In 40% of natural miscarriages, no cause can be identified."

Source: A.E. Beer, Clin Obstet Genecol 13#:115, 1986

Sources like this show us not only how common miscarriages are worldwide, but also how hidden their sources can be, potentially caused by factors unseen or trivial things.

Even a sudden feeling of disgust from dirt can cause a miscarriage—while not immediately, it may negatively affect her developing fetus. This is how the "Nimukei Yosef" explained the Talmud (in Moed Katan 18a), that nails can harm a pregnant woman because of their repulsiveness. The "Ran" also explained this Talmud in Moed Katan and cited the source of concern from nails: "Some interpret it as due to sensitivity"—meaning, pregnant women are sensitive to any foul smell or unpleasant sight, sometimes unable to tolerate even scents others won't notice, and notes that some interpret it for a spiritual reason.

You might now ask, what is so repulsive about nails?

Well, nails aren't something we'd like to leave on the floor of a room or on a table in the living room, and almost anyone would shy away if you asked them to pick up someone else's nails from a table.

However, historical evidence suggests that in the time of our sages, nails were considered repulsive not only by especially sensitive women but by ordinary women of the towns (a clear evidence of this can be found in the Talmud, Nedarim 49b).

It is important to emphasize that even today, we must continue to be cautious for sensitive women, as even a single miscarriage is not a matter to be taken lightly! Such an important issue is not statistical, especially given the fact that many commentators mainly emphasized the spiritual reason.

For example, the ancient author of "Menorat HaMaor" (Rabbi Isaac Aboab) further writes that there is a spiritual reason for this practice (in Chapter 10 of his book): "In the defilement of the nails, the quality of judgment is aroused, and burning them from the world arouses the quality of kindness, therefore our sages said: 'the one who burns them is pious.' A person should distance themselves from ugliness, so they won’t give room to the quality of judgment"—we see that the spiritual reason described by the author of "Menorat HaMaor" is also related to the ugliness of nails and the quality of judgment that such ugliness might awaken during pregnancy, a sensitive time in a woman's life. Kabbalists have delved deeply into this mystical idea.

Also, the "Ba'er Hetev" in his commentary on the Shulchan Aruch (260:2) quotes "Tola'at Yaakov," saying that before the sin of Adam, his entire body was covered with a garment like a nail, and then this garment was removed, remaining only on his hands and feet nails, and since the woman caused this sin, she is dangerously at risk of miscarrying if she encounters them.

Special thanks to Rabbi Zamir Cohen and Rabbi Yaakov Moshe Segal for enlightening their comments.