Sexual passages from the 20s to the 50s

The (mostly) fabulous 40s

Hormone levels are starting to decline, but midlife can be a time of sexual reawakening. Many women find that they're less burdened by the stressors -- children, financial uncertainty -- that can undermine desire in the 30s.

According to the NHSLS, the prevalence of sexual problems in women tends to decrease with advancing age. Like women in their 30s, fortysomethings are at ease with their sexual selves, but now they have the time and energy to enjoy this aspect of their life. Even if you experience a decline in interest, you may find that you can achieve new heights of sexual satisfaction. "Women [at this age] know what they want sexually and are not afraid to ask for it," says Sheryl Kingsberg. (The sad irony is that, with the passage of time, sexual problems become more prevalent in men; see "The Keys to His Desire,")

This is also the decade when women enter perimenopause, the period preceding menopause, when production of estrogen and testosterone begins dropping off. Perimenopause typically kicks in at age 46. About half of all women over 45 experience some symptoms, including irregular periods, lower libido and vaginal dryness. But a decline in sex drive doesn't mean sex can't be great. "You might not have the spontaneous interest, but your ability to achieve orgasm doesn't change in your forties," says Kingsberg.

Many perimenopausal women are prescribed birth control pills to help stabilize hormonal fluctuations and ease symptoms. Of course, the Pill also protects against unwanted pregnancy, which can occur during this transition. Although the Pill may interfere with desire, it may also help a perimenopausal woman feel like herself again--and perhaps more in the mood for sex.

Disorders of the thyroid gland, which produces hormones that stimulate body functions, are common in women over 40. By age 40, 1 in 15 women have thyroid problems; by age 50, 1 in 10 women do. Hypothyroidism, in which the gland secretes too little hormones, is a major cause of low libido. Women with the condition also experience fatigue, weight gain and depression. Fortunately, treatment with synthetic thyroid hormone helps relieve symptoms.