Ethinylestradiol

How ethinylestradiol works in a combined pill

Ethinylestradiol, written ethinyl estradiol in the United States, is a synthetic oestrogen, a lab-made version of one of the two female sex hormones. It is absorbed reliably when swallowed, which is why it is the oestrogen used in most combined pills. On its own it does not prevent pregnancy. Every listing here pairs it with a progestin or with cyproterone acetate, and the two work mainly by stopping the ovaries releasing an egg each month. The partner hormone also thickens the mucus at the cervix, and the oestrogen keeps the cycle steady for as long as the tablets are taken.

The nine listings in the range

All nine are tablets, in the women's health range. What separates them is which hormone comes with the oestrogen and the dose of each.

Levonorgestrel appears in Levlen at 0.15mg with 0.03mg ethinylestradiol, and in Alesse, listed in more than one strength.

Desogestrel is the partner in Desogestrel And Ethinyl Estradiol and Novelon, both 0.15mg with 0.03mg ethinylestradiol, and in Femilon at 0.15mg with 0.02mg — the lowest oestrogen dose in the range.

Drospirenone is the progestin in Yasmin, 3mg with 0.03mg ethinylestradiol. Yasmin is also the listing whose stated uses include acne and menstrual symptoms alongside pregnancy prevention.

Norgestrel is the progestin in Ovral, which comes in several strengths.

Cyproterone acetate, an anti-androgen, is the partner in Diane 35 and Cyproterone Acetate And Ethinylestradiol, both 2mg with 0.035mg ethinylestradiol. They are bought for severe acne and excess facial or body hair (hirsutism) in women, and they prevent pregnancy while they are taken, so no second hormonal contraceptive is used alongside them.

Taking a combined pill

One tablet a day, at the same point in the day, following the order printed on the pack. Many packs hold 21 active tablets followed by 7 inactive or iron tablets, or a seven-day break; some contain active tablets only. The pill works only while it is taken regularly, so it is worth carrying on through spotting or a mild upset stomach rather than stopping mid-pack. With Diane 35 and its unbranded twin, skin and hair improve slowly, over several cycles.

Side effects, common and serious

Nausea, headache, breast tenderness, mood changes, weight change and bleeding between periods are the ones people notice most, and spotting is common in the first few packs before it settles. A blood clot is the serious risk: swelling or pain in one leg, sudden chest pain or breathlessness, or a severe headache that arrives out of nowhere. Sudden vision changes, weakness or numbness in an arm or leg, and trouble speaking need urgent treatment.

Clot risk and what interacts

Smoking and being over 35 both raise the chance of a clot, a heart attack or a stroke on a combined pill, and together they push it higher. The pills are not used by anyone who has already had a clot in a leg, lung or eye, a heart attack, a stroke, or chest pain from narrowed heart arteries, and they are not taken during pregnancy. Some medicines can make them work less well, including rifampicin, a few epilepsy medicines, some HIV medicines and St John's wort.