With most big proponents of the paleo diet being male and the general taboo against this subject, it's not surprising that menstruation and the paleo diet is little discussed. That's a shame, because the beneficial effects of the paleo diet on menstruation is one of the main reasons I keep to the diet.
In most of the modern world, getting your period is a pain. It can last as long as a week and be accompanied by all manners of maladies ranging from irritability to stomach upset. Young women are getting their period earlier and earlier, at the ages of 11 and 12. This has been tied to disease later in life.
It's hard to know what menstruation was like in the paleolithic, but the modern hunter-gatherers studied provide some insight. Foragers, and most women in the rest of the world, get their period around 16. That makes sense because if women started earlier it might make for risky pregnancies. In Nisa: The Life and Words of a !Kung Woman, menstruation is described as a "thing of no account." It's the conventional narrative that menstruation would have been rare for hunter-gatherers, but this is not true. It would have been less because of breast feeding and pregnancy, but still part of the female experience.
This excellent article about that myth talks about how sometimes !Kung women will have periods but will have not released an egg. It also talks about the myth that exercise causes amenorrhea
I learned, by studying runners, what is true for all women - ovulation and menstruation are not the same. Regular periods can and do occur with no ovulation or with disturbed ovulation[8,13,14]. However, like most doctors (and consequently, ordinary women), Is Menstruation Obsolete? implies that periods mean ovulation. It also infers that amenorrhea is (just) anovulation. In fact, amenorrhea means both estrogen and progesterone levels are low-a situation that always causes fast bone loss and the risk for osteoporosis.
She contrasts low fertility caused by living an active and natural life, with the Western illness of amenorrhea, which seems to be unrelated to those things.
My own experience is that prior to starting the paleo diet, I had very heavy periods lasting as long as a week and accompanied by irritability, stomach sickness, and headaches. After I had been on the paleo diet for awhile, my periods became shorter, lighter, and easier. The times I have gone off the paleo diet and had bad periods again have been a huge incentive to stick with the diet.
Why are my periods so much better now? Well, the ratio of omega-3 to omega-6 has been linked to PMS. The reduction in body fat also probably decreased the length of my period.
The problems with modern periods can be linked to various modern habits from contraceptive pills to environmental toxins to delayed childbirth. However, it's clear that appropriate nutrition plays a role.
Some women have reported amenorrhea on the paleo diet. The causes of amenorrhea seem to be varied and some are serious, so a visit to a doctor might be in order.