21כָּל מָקוֹם שֶׁנֶּאֱמַר (ויקרא יב ד) "תֵּשֵׁב" לְזָכָר וְלִנְקֵבָה וּלְנִדָּה כֵּיצַד דִּינָה. תִּהְיֶה אֲסוּרָה לְבַעְלָהּ י"ד יוֹם כְּיוֹלֶדֶת נְקֵבָה. וְאִם רָאֲתָה דָּם בְּיוֹם אֶחָד וּשְׁמוֹנִים הֲרֵי זוֹ סְפֵק נִדָּה. וְכֵן אִם רָאֲתָה בְּיוֹם ע"ד וּבְיוֹם פ"א הֲרֵי זוֹ סְפֵק נִדָּה. וְכֵן אִם רָאֲתָה בְּיוֹם אַרְבָּעִים וְאֶחָד אַף עַל פִּי שֶׁרָאֲתָה בְּיוֹם ל"ד הֲרֵי זוֹ סְפֵק נִדָּה וַאֲסוּרָה לְבַעְלָהּ עַד לֵיל אַרְבָּעִים וּשְׁמוֹנָה כְּיוֹלֶדֶת זָכָר. וְאֵין נוֹתְנִין לָהּ יְמֵי טֹהַר כְּלָל כְּנִדָּה. וַהֲרֵי הִיא כְּמִי שֶׁלֹּא יָלְדָה. וְכָל דָּם שֶׁתִּרְאֶה מִיּוֹם שֶׁהִפִּילָה עַד שְׁמֹנִים יוֹם אִם בָּא בִּימֵי נִדָּתָהּ הֲרֵי זוֹ סְפֵק נִדָּה מֵאַחַר הַשִּׁבְעָה מִיּוֹם שֶׁהִפִּילָה. וְאִם בָּא בִּימֵי זִיבָתָהּ הֲרֵי זוֹ סְפֵק זָבָה שֶׁכָּל יְמֵי מְלֹאת אֵין בָּהֶן וֶסֶת. וְכֵן אִם רָאֲתָה בְּיוֹם אֶחָד וּשְׁמוֹנִים עֲדַיִן הִיא מְקֻלְקֶלֶת וְתִהְיֶה סְפֵק נִדָּה כְּמוֹ שֶׁבֵּאַרְנוּ אַף עַל פִּי שֶׁלֹּא רָאֲתָה אֶלָּא יוֹם אֶחָד וּכְשֶׁיִּקָּבַע לָהּ הַוֶּסֶת אַחַר הַשְּׁמוֹנִים יָסוּר קִלְקוּלָהּ וְתַחֲזֹר לִהְיוֹת נִדָּה וַדָּאִית אוֹ זָבָה וַדָּאִית. וְכֵן מִיּוֹם שֶׁהִפִּילָה עַד שִׁבְעָה יָמִים וְתִהְיֶה נִדָּה וַדָּאִית אִם הִפִּילָה בְּתוֹךְ יְמֵי נִדָּתָהּ כְּמוֹ שֶׁבֵּאַרְנוּ:
What are the laws that apply wherever we said: "She is governed by the laws that apply to the birth of a male and a female and those applying to a niddah"? She is forbidden to her husband for fourteen days like a woman who gives birth to a female. If she discovers blood on the eighty-first day, there is a doubt whether she is a niddah. Similarly, if she discovered uterine bleeding on the seventy-fourth day and the eighty-first day, there is a doubt whether she is a niddah. Similarly, if she discovered [uterine bleeding] on the forty-first day, there is a doubt whether she is a niddah even though she discovered bleeding on the thirty-fourth day. She is forbidden to her husband until the forty-eighth day, as is the law for a woman who gives birth to a male. We do not grant her any "pure days" at all, like a niddah. [The following rules apply with regard to] any bleeding that she discovers from the day on which she miscarried until the eightieth day beginning from seven days after she miscarried. If it is discovered in her "days of niddah, she is a niddah, because of the doubt. And if it is discovered in her "days of zivah," she is a zavah, because of the doubt. For throughout the days after birth, [the previous patterns concerning] the expected times of menstruation do not apply. Similarly, if she discovers uterine bleeding on the eighty-first day, her situation is still problematic and she must consider herself a niddah because of the doubt as explained [above]. [This applies] even if she discovers bleeding for only one day. When she establishes a pattern of menstruation after eighty days, her difficulties will cease and she will be either definitely a niddah or definitely a zavah. Similarly, from the time she miscarried for seven days, she will be definitely impure [like] a niddah if she miscarried in the midst of her days of niddah, as we explained.