I wouldn’t rely on either. My colleague Tieraona Low Dog, M.D., an internationally recognized expert in the fields of integrative medicine, dietary supplements and women’s health, cautions that wild yam, used in a number of hormone-containing medicines, is not an herbal contraceptive and definitely will not prevent pregnancy. Queen Anne’s lace once was used as a sort of "morning-after" treatment; some limited evidence suggests that it might work – emphasis on might.
There are several non-pharmacological approaches to birth control. Of these, your best bets are the ""barrier" methods. Used consistently, diaphragms are 84 percent effective when coupled with a spermicidal cream; used consistently and correctly, condoms are 97 percent effective – and also reduce the risk of sexually transmitted diseases.
Combining two of the natural methods described below can also work. For example, the cervical mucus method plus the temperature method has a 98 percent success rate.
- Cervical mucus: This vaginal discharge reflects estrogen levels at various points in the menstrual cycle. You probably won’t notice any just after menstruation. Later, mucus becomes cloudy and sticky. When it resembles raw egg white, ovulation is near. Avoid intercourse until four days after the mucus disappears or becomes cloudy and sticky again.
- Temperature: Here, you take your temperature with a special "basal" thermometer as soon as you wake. Normal temperature ranges from 97.2 to 97.7 degrees before ovulation. Hormonal changes then boost it by 0.5 to 1.6 degrees. Avoid intercourse until your temperature returns to normal.
- Calendar Method: Avoid sex during the week that you’re ovulating. To calculate this accurately, track your periods for a year. Then subtract 18 from the number of days of your shortest cycle. This is when you are likely to be fertile and should avoid sex. To calculate when you can resume, subtract 10 from the number of days in your shortest cycle. Used alone, the calendar method is 75 percent successful.
- Withdrawal: Withdrawal of the penis from the vagina before ejaculation is the least reliable method, with a success rate of only 60 to 80 percent.
Andrew Weil, M.D.