The progestogen-only pill (POP) contains a progestogen hormone which is like the natural progesterone women produce in their ovaries. POP do not contain estrogen like the Combined Oral Contraceptive Pill (COC). POPs contain different types of progestogens. (POPs containing desogestrel will be named specifically where relevant on this page). If you are not sure what type of progestogen is in your POP, check the patient information leaflet inside your pack or ask your doctor or nurse.