The Science

Period Migraine 101: How & Why It Happens

Period (menstrual) Migraine, or hormonal headaches, are the headaches that happen before or during the period. These headaches occur between 2 days before the period and the first 3 days of the flow.

Period migraines or headaches can be of 4 types:¹

1. Pure menstrual migraine without aura: Headaches or migraine attacks that strictly happen just before or during periods (peri-menstrual) without the accompanying warning signs such as vision disturbances or motor disturbances.

2. Menstrually related migraine without aura: Headaches or migraine attacks that occur in the peri-menstrual period but can occur at other times of the cycle without the accompanying warning signs such as vision disturbances or motor disturbances.

3. Pure menstrual migraine with aura: Headaches or migraine attacks that strictly happen just before or during periods (peri-menstrual) with the accompanying warning signs such as vision disturbances or motor disturbances.

4. Menstrually related migraine with aura: Headaches or migraine attacks that occur in the peri-menstrual period but can occur at other times of the cycle without the accompanying warning signs, such as vision disturbances or motor disturbances.

Menstrual migraines are usually without aura.

Studies in the general population suggest that 4-8% of all women and 18-25% of female migraineurs have menstrual migraine without aura. The prevalence of menstrual migraine with aura has been estimated to be 1.7%-8.1% of female migraineurs in the general population.²

The Science:

The most common cause of period migraine is the decline in serum estrogen (estradiol) levels that occurs shortly before and during the peri-menstrual time period.³

Other factors may also contribute to menstrual or period headaches such as:

1. The release of a chemical called prostaglandins from a shedding endometrium that is responsible for increased pain perception.

2. Decline in serum magnesium levels.

3. Decreases in inhibitory neurotransmitter systems (i.e., serotonergic, GABAergic, etc.) that help control pain.

The causes of period migraines or hormonal headaches being more intense:

1. Due to a decrease in Serotonin, the opioid pathway gets blocked, which increases the pain perception.

2. Reduced serotonin also increases the sensitization of a nerve, responsible for pain perception, called the trigeminal nerve, causing pain around the eye, flashes of light, or blurring of vision.

3. Chemicals that cause inflammation (pro-inflammatory mediators) also increase in the brain.

References

1. Arnold M. Headache classification committee of the international headache society (IHS) the international classification of headache disorders. Cephalalgia. 2018;38(1):1-211.

2. Vetvik KG, MacGregor EA. Menstrual migraine: a distinct disorder needing greater recognition. The Lancet Neurology. 2021 Apr 1;20(4):304-15.

3. Moy G, Gupta V. Menstrual-Related Headache. InStatPearls [Internet] 2022 Oct 4. StatPearls Publishing.