menstrual cycle and contraceptive pills

 FSH 

it causes an egg to mature in an ovaryit stimulates the ovaries to release the hormone oestrogen.

Oestrogen

it stops FSH being produced - so that only one egg matures in a cycleit stimulates the pituitary gland to release luteinizing hormone (LH), which triggers ovulation (the release of the mature egg from the ovary).

Oral contraceptives: contain oestrogen to inhibit FSH