Humans have known for many years that a variety of seizures known as catamenial seizures occur purely in women as a result of variations in sex hormones during the menstrual cycle. It turns out that the various hormones that circulate and alter throughout our reproductive cycle, with its typical 28-day run, can set up conditions in the brain that suppress or encourage seizures in women with epilepsy. Summarizing decades of study into the problem in 2015, scientists wrote in Seizure that "progesterone and its metabolites are anticonvulsant, while estrogens are mainly proconvulsant. The monthly fluctuations in hormone levels of estrogen and progesterone are the basis for catamenial epilepsy."

If you remember your basics about how estrogen and progesterone fluctuate during the menstrual cycle, you'll be able to track how catamenial seizures are influenced by them. Seizures can occur at the stage just before a period because the levels of progesterone, with its anticonvulsant properties, have dropped in the brain; they can also spike during ovulation, when estrogen levels peak, according to these scientists. It's not as simple as saying that these hormones "set off" seizures. It's more correct to think of it as excitability: these hormones either speed up or slow down certain aspects of brain activity, meaning that they might dampen or hasten seizure conditions. This isn't universal to all women, though: Some epileptic women will see very little effect from their hormones at all.

Unsurprisingly, this interaction between hormones and seizures means that, for some women, periods of huge hormonal fluctuation like the beginning of puberty and menopause can be rough. Going through puberty can mean seizures change or develop new patterns, while research in 2005 noted that 40 percent of women going through menopause said their seizure disorder worsened and 27 percent said it improved.

According to research published in 2005, women are more likely to have idiopathic generalized epilepsies (epilepsy with a genetic basis) while men are more likely to experience lesional epilepsy and acute symptomatic seizures (seizures that occur because of some kind of environmental event), and women and men tend to experience different epilepsy syndromes differently.

And in 2014, a study of 1,236 patients found that there are other gender differences: men experienced more "tonic" seizures (which mean a complete loss of muscle tone), while women with some kinds of epilepsy were more likely to experience visual and psychic symptoms, like deja vu or hallucinations, as part of their seizures. Knowing that these differences exist is one thing, but understanding them is another, and many of the distinctions between male and female experiences of epilepsy remain unexplained.

If you've been diagnosed with epilepsy as a woman, even if you don't have catamenial seizures, there are other reproductive risks. Women with epilepsy are more likely than non-epileptic women to have reproductive disorders, from polycystic ovarian syndrome to irregular periods. The Epilepsy Foundation explains:

"The temporal lobes are connected directly to another brain region (called the hypothalamus) that regulates hormone production and ovulation from the ovaries. Disrupting the normal functioning of the temporal lobe by seizures could then disrupt normal ovarian function — hormonal control may be affected which could lead to reproductive disorders. Certain epilepsy medications seem to interfere with hormone regulation too."

The tricky thing about this link is that epilepsy medications appear to play a big role alongside seizures themselves in disrupting reproductive function. Girls with epilepsy who experience more periods than usual, for instance, are warned that the cause could be the disorder or the anticonvulsants used to treat it.

Osteoporosis, an illness that results from prolonged calcium reduction that makes bones more brittle, is more common in women than men, but the problem seems to be exacerbated in women with epilepsy. At least part of the problem, scientists suggest, is that women who take anti-epileptic drugs for a long period face an issue with their calcium levels. "CYP450-inducing antiepileptic drugs (AEDs)," a report from 2011 explains, "upregulate the enzymes which are responsible for vitamin D metabolism, with the effect of converting vitamin D into inactive metabolites, resulting in reduced calcium absorption." If that was Greek to you, it means that the anti-convulsant medications that epileptics take throughout their lives interfere with the body's metabolism of vitamin D, one of the key ways the body absorbs calcium. The result? Less calcium and weaker bones.

A study of 9,700 elderly women in 2004 found that the ones who'd taken antiepileptic drugs were more likely to have brittle bones; their rate of bone loss per year was 50 percent greater than women who hadn't taken the drugs. Part of the problem for epileptics is also increased risk of falls and damage to their skeletons during seizures, meaning more injuries and greater bone issues. Add to this women's greater risk overall of osteoporosis in old age than men, and you have a recipe for large risks for female epileptics. Which seems vastly unfair, if you ask me.

If you have epilepsy or know someone who does, these are important elements of treatment and diagnosis that should be raised with your doctors. Are you getting care that takes into account the gendered aspects of your epilepsy, from helping your calcium levels to noting your hormonal fluctuations? If not, bring it into the conversation.