Ruling on taking birth control pills before the farewell tawaaf
Question

                I am going for Hajj, by Allah’s leave, and my monthly period will come on the 10th (of Dhu’l-Hijjah). I am going to take birth control pills so that I will be able to do tawaaf al-ifaadah.

My question is:

Is it permissible to stop taking the pills after tawaaf for fear of them causing harm, because I am unmarried, or do I have to keep taking them until the farewell tawaaf?
Praise be to Allah.
    Firstly: 

    Tawaaf al-ifaadah is one of the pillars or 
    essential parts of the Hajj, which is not waived in the case of a 
    menstruating woman or anyone else, but the menstruating woman cannot 
    circumambulate the Ka‘bah until she becomes pure (i.e., her period ends and 
    she does ghusl), because the Prophet (blessings and peace of Allah be upon 
    him) said to ‘Aa’ishah when she menstruated: “Do what the pilgrims do, 
    except do not circumambulate the Ka‘bah until you become pure.” Narrated by 
    al-Bukhaari (1650) 

    It says in al-Mawsoo‘ah al-Fiqhiyyah 
    (18/320): There is no difference of opinion among the fuqaha’ that menses 
    does not prevent the woman from doing any of the actions of Hajj apart from 
    tawaaf, because the Prophet (blessings and peace of Allah be upon him) said 
    to ‘Aa’ishah when she menstruated: “Do what the pilgrims do, except do not 
    circumambulate the Ka‘bah. End quote. 

    There is nothing wrong with a woman taking 
    some medicine to prevent menstruation or shorten its duration, so that she 
    will be able to circumambulate the Ka‘bah (tawaaf). 

    Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allah 
    have mercy on him) was asked:

     What is the ruling on a woman using pills 
    to prevent her monthly period during the days of Hajj? 

    He (may Allah have mercy on him) replied: 
    There is nothing wrong with that, because it serves a purpose, so that she 
    will be able to do tawaaf with the people and so that she will not hold her 
    travelling companions back. 

    End quote from Fataawa Islamiyyah 
    (2/185) 

    For more information, please see the 
    answer to question no. 
    112271 and 
    
    36600

    Secondly: 

    With regard to the farewell tawaaf, an 
    exception was made for menstruating women. al-Bukhaari (1755) and Muslim 
    (1328) narrated that Ibn ‘Abbaas (may Allah be pleased with him) said: The 
    people were commanded that the last thing they should do is to 
    circumambulate the House, but an exception was made for menstruating women. 

    Ahmad (3495) narrated that Ibn ‘Abbaas 
    (may Allah be pleased with him) used to say that the Prophet (blessings and 
    peace of Allah be upon him) granted a concession allowing the menstruating 
    woman to leave before doing tawaaf, if she had already done tawaaf al-ifaadah. 

    It says in al-Mawsoo‘ah al-Fiqhiyyah 
    (18/320): The fuqaha’ are unanimously agreed that the menstruating woman may 
    leave (Makkah) without doing the farewell tawaaf, so as to make things 
    easier for her, because of the hadeeth of ‘Aa’ishah (may Allah be pleased 
    with her), according to which Safiyyah (may Allah be pleased with her) got 
    her menses, so the Prophet (blessings and peace of Allah be upon him) 
    instructed her to leave without doing the farewell tawaaf. And it was 
    narrated that Tawoos said: I was with Ibn ‘Abbaas when Zayd ibn Thaabit 
    said: You issue fatwas stating that the menstruating woman may leave without 
    the last thing she does being to circumambulate the Ka‘bah. Ibn ‘Abbaas said 
    to him: Why not? Ask So and So the Ansaari woman whether the Messenger of 
    Allah (blessings and peace of Allah be upon him) instructed her to do that. 
    Then Zayd ibn Thaabit came back to Ibn ‘Abbaas smiling and saying: I see 
    that you are right. End quote. 

    As that is the case, so long as there will 
    be no harm done by your continuing to take those pills until you have 
    completed all the rituals of Hajj and done the farewell tawaaf around the 
    Ka‘bah, that is good, especially when the time between the two tawaafs is 
    usually short. 

    But if you fear that this may cause you 
    harm, then there is nothing wrong with you refraining from it. If you remain 
    pure (i.e., do not get your period), then that is fine, otherwise you may 
    avail yourself of the concession granted by the Messenger of Allah 
    (blessings and peace of Allah be upon him) to the menstruating woman, by 
    leaving without doing the farewell tawaaf. 

    And Allah knows best.