All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
We have not come across the statements of the scholars about this particular issue but they stated that it is not desirable for a menstruating woman to perform ablution when going to sleep, and it is not unlikely that this is also the case with the ablution which you asked about.
An-Nawawi said, Our scholars said, “It is dislikeable for a person in a state of sexual defilement to sleep until he performs ablution, and it is desirable for him if he wants to eat or drink or to have sexual intercourse again with the wife with whom he had sexual intercourse in the first place or with another wife, to have ablution as if for the prayer and wash his private parts in all these cases; and such ablution is not desirable for women in menses or in post-partum bleeding. This is what Ash-Shaafi’i stated in Al-Buwayti [the name of a book] and this is what the scholars of the Shaafi’i School of jurisprudence have agreed upon."
The evidence for this is that the author of the book mentioned that ablution does not affect her state of being in a state of impurity because ablution is not valid [in her case] as long as her state of impurity is continuous.
Therefore, we do not consider that ablution is desirable for a woman in menses when she wakes up because of what we have already mentioned and because the acts of worship are in principle Tawqeefiyyah (i.e. determined by text from the Book of Allaah or the Sunnah of the Prophet , and not amenable to personal opinion).
Allaah Knows best.