Ethinylestradiol: what it is and where it is used

Ethinylestradiol is a laboratory-made oestrogen used with a progestogen in some combined contraceptive pills.

The two hormones work together to make ovulation less likely and to change cervical mucus, making it harder for sperm to pass through. The lining of the womb is also affected. Ethinylestradiol is not a progestogen and is not used alone in a combined pill.

The amount and schedule of ethinylestradiol vary between products. The oestrogen component can help keep bleeding more predictable for some people, while the progestogen provides additional contraceptive action. Hormonal contraception does not protect against sexually transmitted infections. The choice of product depends on medical history, other medicines, smoking status, blood pressure and personal preferences.

Ethinylestradiol is used in some combined oral contraceptive pills. These tablets are taken according to the product’s instructions, often with active tablets followed by a hormone-free interval or inactive tablets. Some people also use combined pills for cycle control or to reduce period-related symptoms, but the suitability of treatment must be assessed individually. A missed tablet, vomiting or medicines that affect hormone metabolism can change protection.

Other contraceptive options include progestogen-only methods, non-hormonal contraception and long-acting methods. They differ in hormones, bleeding effects, how often they need attention and whether they can be stopped immediately by the user. A clinician or pharmacist can compare an option with your medical history and your plans for pregnancy.

Seeing ethinylestradiol listed on a medicine package means the product contains an oestrogen component; it does not identify the whole formulation. Take the medicine exactly as directed and check before starting if you have had a blood clot, have migraine with aura, are pregnant, or take regular medicines. Seek urgent medical help for sudden chest pain, breathlessness, coughing blood, or one-sided leg swelling and pain.

Review the method if your health changes, you develop new migraine symptoms, your blood pressure rises, or you begin a medicine or supplement. A clinician may recommend a different method when the balance of benefits and risks changes. Do not share hormonal contraceptive tablets, and do not double doses without checking the product instructions or receiving professional advice.