Combined oral contraceptives

What it is

Combined hormonal contraception carries estrogen and progesterone together. It comes as combined oral contraceptive pills, one tablet a day; as a contraceptive patch, one patch every week; and as a vaginal ring, placed for 3 weeks with 1 week ring free, with a back up method needed if the ring is out for more than 3 hrs. It works the same way in each form: it thickens the cervical mucous and inhibits ovulation. Its listed advantages are a lower risk of endometrial, ovarian and colorectal cancer, and less acne. It is more than 99% effective if taken correctly, with a failure rate under 1 per 100 woman years; it does not interfere with sex, its contraceptive effect is reversible on stopping, and it usually makes periods regular, lighter and less painful. Beyond the cancers already named it may protect against pelvic inflammatory disease and may reduce ovarian cysts, benign breast disease and acne vulgaris.

How it is treated

The combined pill is also given where the cycle itself is the problem. In primary dysmenorrhea it is one of the hormonal options, taken 3 weeks on and 1 week off. It is one of the hormonal options for uterine fibroid, alongside the levonorgestrel intrauterine system. In polycystic ovary syndrome it is directed at menstrual irregularity and hyperandrogenism and is usually given with metformin for insulin resistance and obesity; it is also one of the drugs used for hirsutism, with eflornithine or antiandrogens where hirsutism does not respond. A GnRH agonist can be used instead of the combined pill, but not in women with osteoporosis.

What to do about missed pills depends on how many were missed:

• One missed pill: take the missed pill.
• Two or more missed pills: take the last missed pill and use an alternative method, condoms, for the next 7 days.

Any postpartum woman should have contraception after day 21, but the combined pill is contraindicated in the first 6 months in lactating women. How it is taken matters as much as what it does. If it is started within the first 5 days of the cycle no additional contraception is needed; started at any other point, an alternative such as condoms is used for the first 7 days. It should be taken at the same time every day, and is taken for 21 days then stopped for 7, giving bleeding similar to menstruation; intercourse during the pill-free period is only safe if the next pack is started on time. Its efficacy may be reduced by vomiting within 2 hours of taking a pill, or by liver enzyme inducing drugs. After 40 it has its own uses: in the perimenopausal period it may help maintain bone mineral density and reduce menopausal symptoms. The preparation is named too: a pill containing less than 30 of ethinylestradiol may be more suitable for women over 40 years, though the unit beside the 30 does not print on the page. It can be continued to 50 years, after which she switches to a non-hormonal or progestogen-only method; a woman on a non-hormonal method stops contraception after 2 years of amenorrhoea if under 50, and after 1 year if 50 or over.