Like Alibubbles, I've had migraines for over 25 years.
It is quite common for them to disappear during pregnancies (allergies tend to vanish as well).
Imagran is a good drug to try if you have very severe migraines, but is only available on prescription and MUST be taken within minutes of the onset of an attack.
Don't miss meals - low blood sugar can set off an attack. If you have advance warning, such as flashing lights and auras, try breathing into a paper bag. Migraines are caused by the narrowing, and then re-widening, of blood vessels. By breathing into a bag you absorb more carbon dioxide and the blood vessels open up again. Unfortunately this also only works if you react quickly to the symptoms.
If you suffer from regular migraines, doctors can prescribe some preventative treatments but these have to be taken on a daily basis. Try keeping a daily diary for a while, noting everything you eat/drink and rough details of what you've been up to that day. After a month or two you should be able to spot if there are any particular triggers (chocolate/cheese/red wine are very common) which you can then avoid in the future.
Migraines do run in families - kids can suffer from migraines but are not always diagnosed very early because they don't have classic headaches - they have tummy aches instead. So if you suffer from them and your kids get recurrent tummy aches for no known reason, mention migraine to your doctor.
And if it's any consolation, migraines do diminish with age - and tend to vanish completely at the menopause!