Do you keep missing your period?

An oestrogen-progestin challenge, administered using combined oral contraceptive pills, is one of the ways of investigating the cause of secondary amenorrhoea. — TNS

When a woman passes menarche (her first period) and does not menstruate for at least six months, it is called secondary amenorrhoea.

Secondary amenorrhoea is commonly caused by pregnancy, lactation and menopause.