It has been known since 1972 (1) that ca. 10% of all women that start oestrogen supplements develop migraine about six months later.

In Denmark around 700,000 women take oestrogen either as birth control (450,000 women)or as supplements against osteoporosis (250,000 women) (2). It means that about 70,000 women have this self-inflicted type of oestrogen migraine.

Contraceptive pills are mainly prescribed to women between the ages of 21 and 33 years. Up to 25% of this age group reports to have had at least one migraine attack during the last 12 months (data from USA, but there is no reason to believe Denmark should be much different).

Approximately 450.000 Danish women between the ages of 20 and 49 take oestrogen as birth control. Unfortunately we do not know how many of these suffered from migraine attacks before they began the oestrogen treatment. But we know that around 10% of those women that starts the oestrogen birth control treatment develop migraine during the first 6 months of treatment, that is, they did not have migraine before they began to take oestrogens. So we can assume that 45.000 Danish women suffer from migraine prompted by their oestrogen supplements.

Statistically seen around 10% of the women taking oestrogen probably had migraine before they began to take the oestrogens, so maybe the true number of induced oestrigen migraineurs in the fertile ages is around 40,000 women, while around 110.000 women have migraine prompted by their natyral oestrigen variations. For the sake of good order it must be mentioned that some women also experience a decline in their migraines when they start an oestrogen treatment.

Approximately 250.000 women after menopsuse also take oestrigens. These would not have hormonal migraines if they did not supplement their hormones, as their natural oestrigen variations have more or less disappeared. However, the oestrogen supplements may cause 25.000 older women to suffer from migraines.

A total of 65.000 Danish women suffer from migraine attacks because they want oestroigen supplements, either as birth control or after menopause.

Migraine may also be triggered by other causes than hormones. The major trigger may be food items. Up to 5% of all men, women and children may suffer from this type of migraine. The total number of migraineurs suffering from food migraine, 'natural' oestrigen migraine and self inflicted oestrogen migraine are shown in the graph.

There is no data for how many migraineurs react to cold, a stuffed nose or other factors.

(1) U. Larsson-Cohn , P. O. Lundberg, 1972. Headache and treatment with oral contraceptives. Acta Neurol Scand 46, 267-278.

(2) General statistics from Lægemiddelstyrelsen on the sale of medicine in 1999.