סימן קנג סעיף א
כָּל אִשָּׁה שֶנֶּעֶקְרָה מִּמְּקוֹרָהּ טִפַּת דָּם, אֲפִלּוּ כָּל שֶׁהִיא, יִהְיֶה בְאֵיזֶה אֹפֶן שֶׁיִהְיֶה, בֵּין בְּטִבְעָהּ, כְּדֶרֶךְ הַנָּשִׁים לִרְאוֹת בִּזְמַנִּים יְדוּעִים, אוֹ שֶׁלֹּא בִזְמַנָּה וַאֲפִלּוּ אֵרַע לָהּ אֵיזֶה אֹנֶס, אֲשֶׁר מֵחֲמַת זֶה יָצָא מִמְּקוֹרָהּ דָּם, הֲרֵי הִיא טְמֵאָה נִדָּה, עַד שֶׁתִּסְפֹּר שִׁבְעָה נְקִיִים וְתִטְבֹּל כָּרָאוּי. וְכָל הַבָּא עָלֶיהָ בְּטֻמְאָתָהּ, חַיַב כָּרֵת, וְכֵן הִיא חַיֶבֶת כָּרֵת. וְעַל הַנְּגִיעָה דֶּרֶךְ חִבָּה, חַיָבִים מַלְקוּת.
A woman from whose womb there issued a drop of blood, be it ever so small, regardless of the circumstances, whether it is in her nature, as some women, to have a regular period or an irregular period; even if she experienced some sort of accident which caused blood to issue from her womb, she is a niddah (menstrually unclean), until she counts seven clean days, and properly performs the ritual immersion. Anyone who cohabitates with her when she is menstrually unclean, receives the punishment of koras.1The koras for this sin includes shortening of the life span to sixty years, and some say to fifty years (see Tosafos Maseches Shabbos 25a and Tosafos Maseches Yevamos 2a). Also his children die during his lifetime (Tosafos Yevamos 2a). And if he has no children now, he will never have any later (Rashi on Leviticus 20:20). Also see Rambam on Maseches Sanhedrin Chapt. 9 that when one dies he also receives a punishment for koras in the next world, as death is not an atonement for it. She too receives the punishment, koras. For touching in an intimate manner, their punishment is flagellation.2This is de’oraisa according to the Rambam.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)