Why were the secretions of a woman's private parts considered to nullify ablution despite being pure and not defiling clothes?

The moisture emanating from a woman's private parts nullifies ablution (Wudu), whether it originates from the uterus or the bladder. Moisture originating from the uterus is pure and does not defile clothes or the body. However, moisture resulting from the bladder is impure (najis) and requires precaution and covering the area. Ablution for this moisture is only required for each prayer if ritual purity is broken by another impurity. It is recommended to take precaution regarding uterine discharges to avoid scholarly disagreement, and because it might mix with something impure, and the jurisprudential rule is to prioritize prohibition when something is both permissible and prohibited.