Is ululation forbidden in Islam?

We do not know what indicates that ululations are forbidden if they are uttered by women alone, but they are forbidden in the presence of someone who enjoys them.

It is disliked for a woman to raise her voice if there is a fear of someone enjoying hearing it, whether this is at funerals or weddings, and whether it is ululations or not.

The voice of a non-mahram woman is not considered 'awrah according to the sound opinion of the madhhab, but it is forbidden to derive pleasure from hearing it.