What is the ruling on fasting and prayer upon seeing a brownish discharge or light bleeding that does not last for a full day and has no symptoms of menstruation, while using birth control pills compatible with breastfeeding that stop menstruation?

As long as the duration of bleeding does not reach a day and a night, it is not considered menses according to the majority of scholars, and prayer and fasting are obligatory, and there is no need to make up the fasting or perform ghusl afterwards; because it is blood of illness and istihada (irregular bleeding). However, according to the Malikis, it is menses, and performing ghusl after its cessation is good as a precaution and to avoid disagreement.