Finally, in October, Depo-Provera -- an injectable hormone that prevents pregnancy for three months -- was approved by the FDA. Large-scale studies and availability are pending.
Another controversial contraceptive option is the intrauterine device, or IUD. After insertion by a physician, this small metal device prevents pregnancy by stopping eggs from implanting in the uterine wall.
The user need do nothing more than periodically check that the IUD is still in place.
IUDs are at least 95 percent effective.
Some experts says the IUD is ideal for middle-aged women. Others argue that this is precisely the group that shouldn't use them.
Women with uterine fibroids -- more common after age 40 -- are advised not to use them. And IUDs may cause severe cramps, a heavy flow and irregular bleeding.
Women who become pregnant while using IUDs have a higher risk of ectopic (non-uterine) or septic (infected) pregnancies -- often fatal to both mother and child. Therefore, those using IUDs are advised to check every missed period with their doctor. Most seriously, IUDs can occasionally perforate the uterus, a medical emergency requiring immediate attention.
And IUD use is associated with an increased risk of pelvic-inflammatory disease, an infection that can scar the fallopian tubes and leave women sterile.
Barrier methods, which include condoms, diaphragms, cervical caps and sponges, are quite effective for mature women.
"Older women generally have intercourse less frequently and withthe same partner," Dr. Hammond says. That's important because the most frequent reason barrier methods fail is because they're improperly used or not used at all.
"For couples having intercourse less frequently, it's not necessary to have a contraceptive that works every day of the month," Dr. Bohon says. "If you examine the statistics of people correctly using spermicidal foam with condoms, it's a very effective method."
Under ideal conditions, barrier methods can be up to 98 percent effective, although typical users can expect 80 percent to 90 percent effectiveness.
Most importantly for women not involved in monogamous relationships, barrier methods offer increased protection from sexually transmitted diseases.
And spermicidal jellies, creams and foams alleviate vaginal dryness, which may be more of a problem during middle age.
On the negative side, condoms can break or come off, sponges can crumble, and diaphragms and caps -- which fit against the cervix and block sperm's entry -- can become dislodged.
Sponges, diaphragms and caps should not be used during menstruation and may not be appropriate for women with pelvic conditions such as a prolapsed uterus.
Whether for religious or philosophical reasons, some women rely on natural family planning, or fertility-awareness methods.
This requires strict attention to a calendar and to the body in order to monitor temperature changes and mucus secretions.
It's moderately effective for those willing to abstain from intercourse during fertile times, but should be approached more cautiously as women age and their natural patterns become less regular.
Even if this method has proven successful for a woman in the past, she would be wise to consult her doctor about it as she enters menopause to better determine when -- and if -- ovulation is taking place.