Final answer:
After stopping oral contraceptives, it can take up to several months for the pituitary gland to start up the hormonal cycle again.
Step-by-step explanation:
The pituitary gland is responsible for controlling the hormonal cycle. After stopping oral contraceptives, it can take up to several months for the pituitary gland to start up the hormonal cycle again. This is because oral contraceptives contain hormones that suppress the natural hormonal cycle. Once the body adjusts and the hormones from the contraceptives are cleared, the pituitary gland will resume its normal function and regulate the menstrual cycle.