Which is more sinful: praying with the possibility of not being in a state of purity (menstruation), or abandoning prayer with the possibility of being in a state of purity?

A Muslim woman must fear Allah and attend to her religious matters. She should learn what is unclear to her, especially issues specific to women, such as menstruation (hayd) and irregular bleeding (istihadah), for each has its own specific ruling and implications. With regard to menstruation, a woman is either a beginner (mubtada’ah) or has a regular cycle (mu’tadah).