Do we depend a Bedika on an injury even during the Shiva Nekiyyim?
Some Poskim rule that during the seven clean days one cannot depend a Biblical sighting of blood [i.e. Hargasha or Bedika], on an injury. Other Poskim rule that even during the seven clean days one can depend a sighting of blood, on an injury that is verified to release blood. Practically, the custom of all Morei Horas is like the latter opinions, to depend a Bedika sighting on an injury. Nevertheless, even according to the latter opinion, certain Bedikas done during the Shiva Nekiyim must be free of blood in order for the Shiva Nekiyim to be valid, as explained next.
If a woman has a bleeding injury during Shiva Nekliyim, how is she to perform the Bedikas of Hefsek Tahara and Shiva Nekiyim?
Some Poskim rule she does not require any Bedika, and is to simply supervise that she does not have a flow during the Hefsek Taharah and Shiva Nekiyim. Other Poskim rule she must achieve a clean Bedika by the Hefsek Tahrah and during one day of the Shiva Nekiyim. Some Poskim write a clean Bedika must be achieved on the first day of Shiva Nekiyim [or the 7th day]. However, from other Poskim it is evident that the clean Bedika can be achieved during any day of the Shiva Nekiyim. Others rule that a clean Bedika must be achieved on both the first and seventh day of Shiva Nekiyim. Some Poskim write she is at the very least to do a Kinuach on the other days of Shiva Nekiyim. [Practically, she must achieve a clean Bedika for her Hefsek Taharah and her first day of Nekiyim. Some Rabbanim require a clean Bedika also on the seventh day. If her injury only releases blood due to friction of a Bedika, then on the other clean days, she is to externally wipe herself to check for blood. In a case that it is not possible for a woman to ever achieve a clean Bedika and become pure, she is to speak with a Rav regarding whether she can rely on the first opinion, and how it is practically done.]
How to achieve a clean Bedika: If she knows where the injury is found she can cover the injury, or circumvent it, and check herself in the other areas. Otherwise, she is to go to a Bodekes on the day of Hefsek Taharah and on the first and last day of Shiva Nekiyim. The Bodekes enters a machine to open her area and checks the area with a Bedika cloth, taking care to overpass the wounded area. Some Rabbanim however say that she does not need to go to the Bodekes on the last day and can do the Bedika herself, and be Toleh if finds blood.
How deep to insert: A Bedika is only valid if it enters the full depth of her area, as deep as she can reach with her finger. If she did the Bedika to the proper depth on even one day of the Shiva Nekiyim it is valid even if she did not go through this depth on the other days. If a woman has an injury by her cervix some Poskim rule it is permitted for her to do a Bedika only into half the depth of her vagina.
How many chances does she have to achieve a clean Bedika on the 1st and 7th day? Some Rabbanim learn that so long as she achieves one clean Bedika on the first and seventh day, it is valid even if she tried numerous times that day.
May she wash her area prior to the Bedika? A woman who suffers from a bleeding injury may wash out the area prior to doing the Bedika.
 See Shiureiy Shevet Halevi 187/5-3 p. 72; Taharah Kehalacha 17/18; Nitei Gavriel 56 footnote 26
Teliya in first three days: Although, in general, we are not Toleh even a Kesem during the first three days [Rama 196/10; see Aruch Hashulchan 196/33 and Shiureiy Sheivet Halevi p. 291 for why], nevertheless, in a case that we know for certain that an injury releases blood, then we are Toleh even during the first three days. [Rama ibid] Now, although there are Poskim who rule we are never Tole during the first three days, even if the injury certainly releases blood [Shach 196/13; Pischeiy Teshuvah 190/39] nevertheless, most Poskim rule like Rama. [Toras Hashelamim 196/14; Aruch Hashulchan ibid; Shiureiy Sheivet Halevi p. 295] Furthermore, it is possible to learn that even according to the stringent opinion, it only applies within three days of the start of the sighting of blood, and not the firs three days of Shiva Nekiyim. [Degul Merivava, bought in Aruch Hashulchan ibid] Practically, Rabbanim are not accustomed to ask what day of Shiva Nekiyim the woman is in when being Toleh. [Aruch Hashulchan ibid]
 Degul Merivava 187; Nodah Beyehuda 49 and 57
 The reason: As the allowance to depend a sighting of blood on an injury is only in cases that she is pure, and hence has a Chezkas Taharah [see Shach 187/19], however when she does not have a Chezkas Taharah, such as during her days of seeing blood and the seven clean days, then perhaps we cannot depend it on an injury. [Noda Beyehuda ibid]
 Chasam Sofer 42, 144; Avnei Miluim 23; Opinion in Sidrei Taharah ibid; Aruch Hashulchan 196/25
 The reason: As once she has done a successful Bedika for her Hefsek Taharah she no longer has a Chezkas Roeh, and thus we have no reason to give her a Chazakah that she is seeing period blood, and therefore here too we can depend the sighting on an injury. [Chasam Sofer ibid]
 See Shiureiy Shevet Halevi 187/5-3 p. 72; Taharah Kehalacha 17/14-18; Nitei Gavriel 56 footnote 26
 Chasam Sofer 177, brought Pischeiy Teshuvah 196/5; Noda Beyehuda Kama 59; Avnei Miluim 23; Tuv Taam Vadaas 1/198; Levanon Neta 196/4; Malbushei Taharah 196/8
 The reason: As Biblically, a Bedika is not required at all during the Shiva Nekiyim. [ibid]
 Chavas Daas 196/3, brought in Pischeiy Teshuvah 196/5; Noda Beyehuda Tinyana 134 in end; Tzemach Tzedek Y.D. 123 regarding a woman with injury “It suffices for such a woman to do a Hefsek Taharah and the first day of the Shiva Nekiyim, and the other six days she is not to check”; Chochmas Adam 117/12 regarding Chashash Iggun; Aruch Hashulchan 196/25 “Those women who suffer from injury in the womb are told to do a clean Bedika for the Hefsek Taharah and one clean Bedika on any day of the Shiva Nekiyim, and so is how Rabbanim Pasken.”; Beis David 2; Maharash Engel 1/50; Taharas Yisrael 196/29-30 and Beir Yitzchak 98 “Tis is obvious according to all”; Beis Efraim 48; See also Kinas Sofrim 45; Malbushei Taharah 6-8; Taharah Kehalacha 17/14-17 footnote 39
 The reason: As some Poskim rule that even one Bedika in any of the seven days suffices, and in a time of need one may be lenient like this opinion.
 Tzemach Tzedek Y.D. 123 regarding a woman with injury “It suffices for such a woman to do a Hefsek Taharah and the first day of the Shiva Nekiyim, and the other six days she is not to check”; Noda Beyehuda Tinyana 134 in end; Shiureiy Shevet Halevi 187/5-3 that so is final ruling; All the Melaktim [Taharah Kehalacha ibid and others] write that she is to have a clean Bedika on the first day. Vetzaruch Iyun for their source, being the Chavos Daas never writes that one cannot be Toleh the first day on an injury.
 According to the lenient opinion followed by this approach there is no difference if the clean Beidka was achieved on the 1st or 7th day. [See Taharah Kehalacha 17/17]
 The reason: As some Poskim rule a Bedika in the middle days is not valid.
 See Chavos Daas ibid “If she checked herself onetime in the morning of one of the days of Shiva Nekiyim and it was pure, then we establish all her other days as pure as well and depend any blood found to be from a Maka.” This implies that even if the first days Bedika came out with blood it is still valid, and we do depend the first days Bedika on an injury. Aruch Hashulchan ibid; Chochmas Adam ibid; Taharas Yisrael 196/29-30 and Beir Yitzchak 98 “Tis is obvious according to all”; Beis Efraim 48; See Taharah Kehalacha 17 footnote 39
 See Sidrei Taharah 196/15 that implies she needs to do on 1st and 7th; So told me Rav Asher Lemel, and so writes Taharah Kehalacha ibid “If possible she should also do one on the 7th day” however I have not found this in the Poskim, and on the contrary the Chavos Daas explicitly states it is not necessary to have a clean Bedika more than one time.
 This follows the stringent opinion who rules the Shiva Nekiyim is only valid if a Bedika was done on the 1st and 7th day.
 Tzemach Tzedek ibid; Noda Beyehuda 129; Taharah Kehalacha 17/15
 Shiureiy Shevet Halevi 187/5-3
 So told me Rav Asher Lemel Hakohen; Taharah Kehalacha ibid writes “If possible she should also do one on the 7th day”; Rav Yurslovsly ruled to me that she must do a Bedika on the 7th day but if it comes out dirty she can still be Toleh.
 See Taharah Kehalacha 17 footnote 36
 Tzemach Tzedek Y.D. 123 based on Zichros Yosef Y.D. 10 that she can circumvent the area of the wound; Emek Sheila Y.D. 44; Nefesh Chayah 63; Shevet Halevi 7/3; Kaneh Bosem 1/95-2; Taharah Kehalacha ibid that so he received in Shmiush Chachamim; Nitei Gavriel 56 footnote 27 that so he received from his Rabbanim
 See Sidrei Taharah Taharah Kehalacha ibid; Rav Kohen 5th of Kisleiv
 Rav Yuroslovsky
 Taharah Kehalacha 16/29; Shiureiy Shevet Halevi p. 291
 Michaber 196/6
 Terumos Hadeshen; Bach; Beis Yosef; Sidrei Taharah; ; Piskei Dinim 196/11; Shaareiy Tohar 16/6; Ben Ish Chaiy Tzav 2/15; Taharah ibid; Shiureiy ibid
 Rama ibid
 Kaneh Bosem 1/97
 Rav Farkash
 Pashut, as so long as she gets one clean Bedika it shows that her period did not come, and the previous Bedikas may all be dependent on the injury.
 Mishnas Yaakov 3/123; Nitei Gavriel 56/5