American Medical Association Family Medical Guide - American Medical Association [245]
Vaginal Ring
The vaginal ring, which is available only by prescription, is a pliable, transparent ring that is inserted into the vagina to prevent pregnancy. The ring continuously releases estrogen and a form of progesterone (progestin) to inhibit ovulation and block implantation of a fertilized egg. The ring stays in place for 3 weeks, and you remove it for the week that you have your period. You insert a new ring at the end of the fourth week. The ring is easier to insert and remove than a diaphragm (see page 471) because it does not require special positioning over the cervix. It is 99 percent effective in preventing pregnancy (but check regularly to make sure it has not been accidentally expelled).
Side effects of the vaginal ring include vaginal discharge or discomfort, or the sensation of a foreign body inside the vagina. Like the birth-control pill, the vaginal ring can increase the risk of blood clots, heart attack, and stroke, especially in women over age 35 who smoke cigarettes.
Natural Methods
The natural method of contraception, sometimes called the rhythm method, attempts to prevent pregnancy by predicting the day in the menstrual cycle when a woman will ovulate and abstaining from intercourse on the potentially unsafe days before and after. Intercourse on the day of ovulation and 3 to 4 days before and after carries a high risk of conception because sperm can live in a woman’s body for as long as 6 days after intercourse (an average of 4 days). A sperm can fertilize an egg during the first 24 hours after ovulation.
Natural birth-control methods are the least reliable form of contraception because they depend on an estimate of the time of ovulation; each woman’s menstrual cycle can vary from month to month, and some women may ovulate more than once during a cycle. You will need to keep records over several months to be able to accurately estimate the pattern of your cycle. There are several ways to calculate the time of ovulation, which occurs in most women about 14 days before the first day of their period.
Temperature Method
In most women, morning temperature (called basal body temperature) rises slightly just after ovulation and does not fall again until shortly before their period begins. Take your temperature each day as soon as you wake up—before you get out of bed or eat or drink anything—using a special thermometer designed to record small changes in temperature. Keep a chart of each temperature recording to determine your pattern of ovulation. Avoid intercourse from the first day of a period until 3 full days after the temperature rise. The disadvantages to this method are that you have no warning when ovulation will occur, and temperature readings can be inaccurate.
Ovulation-Predictor Kits
Ovulation-predictor kits are available over the counter to help you determine when you are ovulating. To use, hold a test strip under your stream of urine and check the strip’s change of color according to the package directions. To prevent pregnancy, avoid having intercourse for 3 to 4 days before and after ovulation.
Mucus-Inspection Method
About 4 days before ovulation, the mucus from the cervix becomes thin, clear, sticky, and plentiful, similar to the consistency of egg whites. To prevent pregnancy, avoid intercourse from the time the wet mucus appears until 4 days after the mucus becomes noticeably reduced and drier after ovulation.
Mucothermal Method
The mucothermal method combines the temperature method and the mucus-inspection method (see previous page). It is the most reliable natural method, especially when performed with the guidance of a trained health care professional. But you must avoid intercourse for at least 3 days after your temperature rises and for 4 days after your mucus thins.
Calendar Method
The calendar method is