A woman with a וסת קבוע performs no bedika — and, indeed, she should not check herself before her husband (שלא יהא לבו נוקפו); without a וסת קבוע, the first three times and the חזקה; the great machloket and the prevailing custom not to require a bedika (Shach); the מסולקת דמים and ro'ah machmat tashmish, referred to sim. 187 (Shulchan Aruch, Yoreh De'ah 186 — 5 se'ifim)
אִשָּׁה שֶׁיֵּשׁ לָהּ וֶסֶת קָבוּעַ — אֵינָהּ צְרִיכָה בְּדִיקָה לֹא לִפְנֵי תַשְׁמִישׁ וְלֹא לְאַחֲרָיו; וְאַדְּרַבָּה, אֵינָהּ צְרִיכָה לִבְדֹּק עַצְמָהּ בִּפְנֵי בַּעְלָהּ בִּשְׁעַת תַשְׁמִישׁ, כְּדֵי שֶׁלֹּא יְהֵא לִבּוֹ נוֹקְפוֹ וּפוֹרֵשׁ.
A woman who has a וסת קבוע (a fixed cycle) — performs no bedika, neither before relations nor after; and, on the contrary, she should not check herself before her husband during relations, so that his heart not be seized with misgiving to the point that he withdraw (שלא יהא לבו נוקפו ופורש).
Shulchan Aruch, Yoreh De'ah 186:1 (excerpt)LEVEL 01
Hebrew text of the 5 se'ifim with a fluent English translation. The woman with a וסת קבוע (no bedika and שלא יהא לבו נוקפו), the first three times without a וסת and the חזקה, the מסולקת דמים (מעוברת, מניקה) and ro'ah machmat tashmish, explained with dignity and practical cases of טהרת המשפחה.
📖 StudyLEVEL 02
In-depth pilpul: the machloket rishonim on the obligation of bedika (Mehaber / Rambam / Rosh against the Shach's reading of the רי״ף, « אין צריך בדיקה כלל, וכן עמא דבר »); the reason of שלא יהא לבו נוקפו and the tension between bedika and shalom bayit; the logic of the חזקה of the three times (מוחזקת that she does not see מחמת תשמיש); the מסולקת דמים (Chacham Tzvi, Maharam Padova — PT); the mutual ne'emanut of se'if 4.
📖 StudyLEVEL 03
Comparative tables (with or without a וסת קבוע, before / after relations, the three times and the חזקה, מסולקת דמים, the machloket Mehaber / Shach), golden rules, classic pitfalls and cross-references (sim. קפ״ד, קפ״ה, קפ״ז, קפ״ט, קצ״ו); memorization of the 5 se'ifim of bedika.
📖 StudyLEVEL 04
Two parts: the approach of Chabad and the shitah of the Tzemach Tzedek (Daat HaRav, in principle), then the halacha lema'asse of the other poskim — Beit Yosef, Rama, Shach (« וכן עמא דבר »), Sidrei Tahara, Chochmat Adam, Aruch haShulchan, Toharat haShulchan, Chacham Tzvi, Taharat haBayit, Shevet haLevi, Badei haShulchan.
📖 StudyIt depends on the woman's status. A woman with a וסת קבוע (fixed cycle) performs no bedika, neither before relations nor after (Shulchan Aruch 186:1) — she relies on the regularity of her cycle. Without a וסת קבוע, the Shulchan Aruch speaks of bedikot for the first three times; if she becomes established (הוחזקה) that she does not see מחמת תשמיש, she need no longer check. But the Shach rules that in truth אין צריך בדיקה כלל — there is no obligation of bedika even without a וסת — and that such is the prevailing custom (« וכן עמא דבר »). This is a great practical machloket: each home follows the ruling of its Rav, and no one decides alone.
The Shulchan Aruch teaches (186:1) that on the contrary, a woman with a וסת קבוע should not check herself before her husband during relations — שלא יהא לבו נוקפו ופורש: so that the husband's heart not be seized with misgiving, which would lead him to withdraw. Here the halachah safeguards serenity and shalom bayit: an excess of checking, far from strengthening the taharah, would cast disquiet into the intimacy. This is the balance proper to all of טהרת המשפחה — the precision of counting the days on one side, sobriety and trust on the other. The concrete measure is settled with your Rav.
The closing se'if of the siman addresses, with gravity, the woman who is רואה מחמת תשמיש — who sees blood on account of relations: if it occurs three consecutive times, she becomes forbidden to this husband, and the whole of its detail is set out in siman 187. This is a matter both halachic and medical: it calls for an imperative referral to a Rav, and often to a physician, never deciding alone. Conversely, a woman who is מסולקת דמים — by nature a בתולת דמים (Chacham Tzvi, cited in Pitchei Teshuva), or by state a מעוברת (a pregnant woman) or a מניקה (a nursing woman, Maharam Padova, cited in Pitchei Teshuva) — is exempt from bedika even without a וסת קבוע, for her body is « cleared of blood ». Here too, the application is decided with your Rav.