Sunan al-fitrah during menses
Question

Is it not permissible for a woman to do the “sunan al-fitrah” during her menses?.
Praise be to Allah.There is no reason why one should not do the “sunan al-fitrah” or keep oneself clean or beautify and adorn oneself, rather the menstruating woman is like any other woman in that regard. 
Rather the menstruating woman is not allowed to pray, fast, circumambulate the Ka’bah (tawaaf), touch the Mus-haf, enter the mosque or have intercourse. 
The scholars of the Standing Committee for Issuing Fatwas were asked: Is it permissible for me to put henna on my hair and hands during my monthly period? 
They replied: 
That is permissible for you, because the basic principle is that it is permissible and there is no shar’i proof to the contrary. End quote. 
Fatawa al-Lajnah al-Daa’imah (5/403) 
Secondly: 
Doing the sunan al-fitrah depends on whether there is a need for that. If a person’s hair or nails have grown long, it is Sunnah for him to hasten to shorten them. 
Al-Nawawi (may Allah have mercy on him) said in al-Majmoo’ (1/340): 
With regard to the time limit for cutting the nails, it depends how long they are– when they grow long one should cut them. That varies from one person to another. The guideline with regard to cutting the moustache, plucking the armpit hairs and shaving the pubes is the same. End quote. 
It is well known that the menses may last for more than a week, and nifaas may last up to forty days, so how can one be enjoined to ignore these sunan al-fitrah and not do them during that time? 
Thirdly: 
Some people believe that the person who is in a state of major impurity should not remove any of his hair or nails. This is a false belief that has no basis in Islamic sharee’ah. 
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) was asked about a man who cut his nails and moustache and combed his hair whilst he was junub – is there any blame on him for that? Some of them referred to this and said: If the person who is junub cuts his hair or nails, then these parts will come and join his body in the Hereafter, and he will be raised on the Day of Resurrection with a measure of janaabah commensurate with what he cut of that, and on every hair will be a measure of janaabah. Is that the case or not? 
He (may Allah have mercy on him) replied: 
It is proven in the hadith of Hudhayfah and the hadith of Abu Hurayrah (may Allah be pleased with them both) that when the person who is junub was mentioned to the Prophet (peace and blessings of Allah be upon him), he said: “The believer does not become junub.” In Saheeh al-Haakim it says: “alive or dead.” I do not know of any shar’i evidence to suggest that it is makrooh for one who is junub to cut his hair or nails. Rather the Prophet (peace and blessings of Allah be upon him) said to one who became Muslim: “Cut off the hair of kufr and get circumcised.” And he told the one who became Muslim to do ghusl, but he did not tell him to delay getting circumcised or removing his hair until after he had done ghusl. The general meaning of his words indicates that both are permissible. Similarly the woman who is menstruating is enjoined to comb her hair whilst doing ghusl, even though combing the hair will cause some of the hairs to fall out. And Allah knows best. 
End quote. 
Majmoo’ al-Fatawa (21/120-121). 
And Allah knows best.