The dispute over the morning-after pill has hinged on the politics of FDA approval and the science of abortion. Did the FDA withhold approval just to placate Bush’s conservative base? Is Plan B really “emergency contraception” or it is really a very early abortion? Now that the morning-after pill has been approved for over-the-counter use, we need to ask ourselves how it will affect the spread of Sexually Transmitted Diseases (STDs). I predict the morning-after pill will induce a new round of increases in sexually transmitted diseases.
I base my opinion on the dynamics of contraceptive failure. We know that contraceptive failure is a function of age, income, and marital status. Younger women, unmarried women, and poor women are more likely to experience a contraceptive failure. Consider the rate of contraceptive failure for oral contraceptives, widely considered the most reliable of all the reversible, non-long-acting contraceptive methods. The failure rate of the Pill is 13 percent for poor married women under the age of 20, and declines to just under half that rate to 5.7 percent, for married poor women over 30. The age-specific failure rate is even more dramatic for cohabiting, but not married couples: For poor cohabiting women under age 20, the failure rate of the pill is 48 percent, while for poor cohabiting women over age 30, the failure rate is a mere 10.8 percent.
The failure rates for condom use are similarly correlated with age, income and marital status. The most successful users of condoms are married women over age 30 who are not poor. Of women in this group whose primary birth-control method is condoms, 6 percent can expect to be pregnant within a year. By contrast, among unmarried poor women under age 20, 23 percent will be pregnant within a year. The most spectacular failure rates are for cohabiting, poor women under the age of 20: 72 percent of them who use condoms as their regular birth control method will be pregnant within a year’s time.
What is going on here? Obviously, the pills don’t know the woman’s age or income. The condoms aren’t surreptitiously trying to enforce “family values,” by breaking more often for women “living in sin” than for married women. The pills are “failing” because the women aren’t taking them. The condoms are “failing” because people aren’t using them regularly. The failure rate in this study is measured as the percentage of women, using a regular method of birth control, who become pregnant within a year’s time. Married women, more mature women, and higher-income women are more likely to take their pills regularly and use condoms consistently. The high failure rates for cohabiting women occur because cohabiting women have more sex than other unmarried women.
What does this tell us about the likely impact of the wide availability of the morning-after pill? For those women who rely on birth-control pills for contraception, MAP will probably not change their behavior. If they are taking the pills but not regularly, they presumably still believe they are protected. They are not likely to get up the next morning and run to the drug store.
But for people who are using condoms but not reliably, the morning-after pill will become not Plan B, but Plan A, the birth-control method of first choice. “Oh honey, stop, we’ve got to put on a condom.” “Don’t worry, baby. I’ll get you the pills tomorrow.”
Even with all the publicity and education surrounding “safe sex,” not everyone at risk for STDs uses a condom every time. Pausing to put on a condom interrupts the flow and spontaneity of the sexual act. Persuading people to do that consistently is a tough sell. It’s even a tougher sell to people who already have another birth-control method, like the Pill. With the advent of Plan B, everyone has a method other than condoms. If you think preaching abstinence is unrealistic, try preaching consistent condom use to people who already have a foolproof birth-control method.
I predict an increase in sexual activity, unprotected by condoms. I also wouldn’t be surprised to see an increase in sexual activity overall, as people believe themselves to be “safe” from pregnancy, due to the availability of the morning-after pill as emergency contraception.
But being “safe” from pregnancy isn’t the same as being “safe” from STDs. Look for an increased rate of STD infections over the next few years.
Information on condom failure rates reported in this article can be found in “Contraceptive Failure Rates: New Estimates from the 1995 National Survey of Family Growth,” Haishan Fu, Jacqueline Darroch, Taylor Haas and Nlini Ranjit, Family Planning Perspectives, 1999, 31(2): 56-63, Table 2.