Menstrual cycle

Immune changes
Populations of Tregs increase peak just before ovulation and bottom out during the luteal phase, just before menstruation.

Progesterone and estrogen have anti-inflammatory effects.

Health effects in ME/CFS
Women who develop CFS report at higher rates a history of irregular cycles, amenorrhea, anovolutory cycles and sporadic bleeding between periods.

Health effects in other conditions
The menstrual cycle can have effects on the timing and severity of symptoms of women suffering from many different conditions, including epilepsy, migraines, asthma, rheumatoid arthritis and irritable bowel syndrome.

Many women with epilepsy have patterns of seizure activity linked to their menstrual cycles, called catamenial epilepsy. Seizure activity increases just before ovulation and just before menstruation.

Abrupt estrogen withdrawal, such as what occurs just prior to menstruation, can trigger migraines. Women with rheumatoid arthritis experienced reduced symptoms after ovulation, owing potentially to the anti-inflammatory effects of progesterone and estrogen.

In a retrospective study, 72% of women with fibromyalgia reported a worsening of symptoms just before their periods.

Managing premenstrual symptoms
Nonsteroidal anti-inflammatory agents are occasionally effective in women with menstrual migraine, as are beta blockers, calcium channel blockers, ergotamine, antidepressants, estrogen and estradiol.

Pathophysiology of menstrual symptoms
Estrogen may directly affect blood vessels by stimulating nitric oxide release. Women with a history of menstrual migraine had a heightened activation of the nitro oxide and L-arginine pathways, especially during the luteal phase.