(No) sex drive: How the menstrual cycle affects libido

Lots of women tell a similar story: There are times when their desire for sex is so extreme that they should put out a warning.

Achtung, baby! My libido's out of control!

But they can also be the best days in a relationship. And then it's all over, almost from one moment to the next. Sex? No, thanks!

That lust, that sexual drive that overpowered them just before, is all but gone. Only the finest seductive artistry has a chance — without it, sex won't even enter a woman's mind.

Science in the swings of sexual desire

In 1980, a study suggested that these swings in sexual desire were influenced by a person's hormone levels, which change during the menstrual cycle.

It found that it wasn't only the direct influence of hormones — such as estrogen and progesterone — but also that these variations in hormone levels had an impact on a person's physical and psychological sense of well-being.

A menstrual cycle begins with the first day of one's period and ends on the day before the next period begins. The duration of a cycle varies from person to person, but anything from 21 to 35 days is possible.

Roughly halfway through the cycle, the woman ovulates.

As in every month, the uterus will have prepared itself for a pregnancy by developing a lining of blood and tissue. That's known as the uterine lining or endometrium.

If there is no pregnancy, the level of progesterone in the ovaries and estrogen in the blood drops so drastically that bleeding occurs. So, at the start of the first half of the cycle, a woman bleeds.

At this point, a woman's sexual desire is relatively low, within limits. That's because of the lower level of estrogen in the blood and the fact that periods can be painful or associated with discomfort.            

That can change suddenly when the so-called follicular phase begins.

Estrogen raises libido

Once the body has shed the uterine lining, the pituitary gland starts producing a follicle-stimulating hormone, and that results in new, maturing follicles.

These ovarian follicles are where eggs are located, and they also produce estrogen.

As the follicles mature, the level of estrogen rises — and, with it, a woman's sexual desire. But not only that: Many women feel more confident during this phase, sport feels easier, and they can concentrate better than in other phases.

Women who use contraceptives such as the pill are mostly spared the hormone roller-coaster ride. Such contraceptives prevent any large changes in hormone levels.

Both the level of estrogen and a woman's libido peak at ovulation. The high level of estrogen causes the release of luteinizing hormone, which in turn causes the ovulation.

The follicle releases the mature egg into the fallopian tubes, where it can be fertilized with sperm for about the next 24 hours. And the estrogen does what it can in those hours to seduce the woman into having sex.

Progesterone inhibits the libido

Meanwhile, the follicle that hosted the egg turns into what's known as the corpus luteum, or yellow body of the ovary. 

This is the second phase of the menstrual cycle. It's known as the luteal phase.

During this phase, the yellow body of the ovary produces some estrogen but mainly progesterone — and progesterone ends the sex party!

The fun and games stop, and things get serious: The uterine lining continues to thicken to prepare for pregnancy. If the woman becomes pregnant, progesterone does what it can to make it stay that way.

But, if the woman doesn't get pregnant, the yellow body of the ovary and progesterone levels decline.

And progesterone clears the stage just in time for the next period and the production of new estrogen to begin. So some women report that their libido rises again before and even during menstruation — at least, that is, compared with the dry spell just before.

This article was originally written in German