For women who don't want the bother of a daily Pill or the extended commitment of Norplant or Depo-Provera, Lunelle offers an effective compromise. Lunelle is administered once a month as a shot in the arm, thigh, or buttock. Each injection contains a progestin called medroxyprogesterone acetate (the same progestin found in Depo-Provera Contraceptive Injection) and a form of estrogen called estradiol cypionate. When given as prescribed, the injections are as effective as birth control pills.

Timing of the shots is critical. The first injection should be given within the first five days of the start of your normal menstrual period. If you are presently using another type of birth control, your doctor will decide the best timing to assure continued contraceptive coverage. Likewise, if you've recently been pregnant or had a baby, you should discuss with your doctor the best time to start the injections.

For optimum protection, the injections must be given every 28 to 30 days—at most, no more than 33 days after the last injection. The date for each injection is determined by the number of days since the previous shot, not by the timing or amount of previous menstrual bleeding. Even if there is no menstrual bleeding, you need to return once a month for your next shot in order to maintain uninterrupted protection against pregnancy. Schedule an earlier appointment if you know you won't be available at the ideal time. If you miss an injection or wait longer than 33 days between shots, your chances of pregnancy go up—and the more days you wait, the greater the risk.

If you have received your injections regularly and miss one menstrual period, be sure to inform your doctor. While the risk of unexpected pregnancy is very low for women who receive the shots on schedule, you still need to be checked by your doctor. If you haven't received the shots on time and miss a menstrual period, or if you miss two consecutive menstrual periods, you may be pregnant and should contact your doctor immediately to determine your status.

When you decide to become pregnant, all you need do is stop the shots. Most women begin to produce eggs again within two to three months after their last injection. As with other hormonal contraceptives, however, delays sometimes occur, especially if your menstrual cycles were irregular prior to starting the injections.