Emicrania e contraccezione ormonale combinata

Why are women with migraine who take the pill or use the vaginal ring or the patch a special case?

Il combined oral contraceptive (COC) pill ('the pill'), the contraceptive vaginal ring ('the ring') e lo contraceptive patch ('the patch') contain the chemical (hormone) oestrogen. They are all called 'combined hormonal contraceptives'. They are generally used for 21 consecutive days, followed by a 7-day break (in which you may have a period).

Taking oestrogen causes you to have a slightly increased risk of having a ictus (compared with the normal risk). If you have migraine without aura, you have a slightly increased risk of having a stroke compared with the normal risk. The increased risk of having a stroke is slightly higher in people who have migraine with aura.

If you take oestrogen and you have migraine the risks increase a little more, because now two risks are present.

• The combination of taking combined hormonal contraception plus having migraine senza aura increases the risk of stroke slightly more than either alone.

• The combination of taking combined hormonal contraception plus having migraine con aura increases the stroke risk by a little more than this, multiplying it by 2 to 4.

This is still a very low risk, but it is an increased risk of something very serious (having a stroke). Doctors therefore advise against using combined hormonal contraception if you experience migraine with aura, as this is puts you at a small but unnecessarily increased risk of something very serious.

You should take advice from your doctor or nurse, as individual circumstances can vary.

This means that the only women with migraine who can take combined hormonal contraceptives are women who are aged under 35, and who had already experienced migraine attacks without aura before they started taking the pill or using the patch.

There are a number of other methods of contraception available for women with migraine who should not take the pill or use the patch. For example, the progestogen-only pill (POP), the progestogen injection, intrauterine contraceptive devices (IUCDs) or the intrauterine system (IUS), and metodi barriera are usually suitable.

If you have frequent or very severe migraines, you may be advised to take treatment every day to prevent migraines.

The National Institute for Health and Care Excellence (NICE) has updated its guidance on headaches, to include extra warnings about the use of some preventive medication for migraine - see 'Further Reading' below.

• Sodium valproate (a medicine usually used to treat epilepsy) should not be used as a preventive treatment for migraine for any women who might get pregnant.

• Topiramato (another medicine usually used to treat epilepsy) can be effective in reducing the frequency and severity of migraines. However:

  • If you are taking topiramate when you are pregnant, there is a risk of birth defects in your baby.

  • Topiramate can make hormonal contraception less effective.

  • It is essential that you use really effective contraception, such as the iniezione contraccettiva, an intrauterine coil oppure Sistema Intrauterino (IUS), or a combination of the COC pill along with a barrier method of contraception.

This means having a good method of contraception is very important for women who are on these medications. As above, there are a number of other methods of contraception available for women with migraine who should not take the pill or use the patch. For example, the progestogen-only pill (POP), the progestogen injection, intrauterine contraceptive devices (IUCDs) or the intrauterine system (IUS), and metodi barriera are usually suitable.

In some women with migraine who take the pill or use the patch, migraine attacks (episodes) can be triggered by the drop in the blood level of oestrogen during the pill-free or patch-free interval.

• So long as these migraine attacks are senza aura AND you were already known to have migraine without aura before starting the pill or the patch, there is usually no need to stop the pill or the patch.

• If they are migraines with aura, you should stop the pill or the patch, and if you have never had migraines of any sort before, you should stop the pill or patch.

If these migraine attacks are without aura but are troublesome and not easily treated with antidolorifici oppure triptans, there are the following options to consider.

Change to a pill with less progestogen

Migraine attacks during the pill-free interval seem to occur less often in women who take a pill with a lower dose of progestogen.

Tricycle your pill

This means taking the pill continuously for three packets (nine weeks) without any breaks, followed by a seven-day pill-free interval. This keeps the level of oestrogen constant whilst you take the three packets. By doing this you have fewer withdrawal bleeds and therefore fewer migraine attacks. It is OK to have only one withdrawal bleed every three packets. Nota: you can only do this with pill types that have the same dose of progestogen for each dose. These are the commonly used types; however, check with your doctor or nurse if you are unsure.

Use an oestrogen supplement during the seven-day pill-free or patch-free interval

This can be achieved in various ways including tablet or patch.

Change to a different method of contraception

The other methods of contraception that might be offered are the progestogen-only pill (POP), the progestogen injection, intrauterine contraceptive devices (IUCDs) or the intrauterine system (IUS), and metodi barriera.

La Dott.ssa Mary Lowth è un'autrice o l'autrice originale di questo opuscolo.