Plan B may not be effective

DEAR DOCTOR » My granddaughter’s college offers “morning-after” pills via vending machine. Using these pills without a doctor’s prescription and oversight can’t possibly be safe, can it? DEAR READER » Between 2006 and 2010, one out of every nine women of reproductive age used some form of emergency contraception — often when other forms of contraceptives had failed. Although the subject raises both religious and ethical questions for some people, the reality is that so many women have already been safely treated with emergency contraception by doctors that some forms of the drugs are now available over-thecounter.

Oral emergency contraception works by delaying a woman’s ovulation, thus lowering the likelihood that sperm will fertilize an egg. Pregnancy rates among 20-something couples is 30 percent if intercourse occurs one to two days prior to ovulation. If intercourse occurs at any random point in a woman’s cycle, the overall chances of getting pregnant are only 4 to 6 percent. Studies of Plan B (levonorgestrel), the medication provided via vending machines at some campuses, show an overall chance of pregnancy of 2.6 percent among women who’ve taken the drug. So in reality, the drug is only about 50 percent effective in most cases.

Note that, if a woman is obese or overweight, the drug is even less effective. Obese women (those with a body mass index of 30 or higher) were four times more likely to become pregnant after taking Plan B than those with a healthy body mass index. Overweight women (BMI of 25 to 29.9) were two times more likely to get pregnant after taking Plan B than normal-weight women.

Plan B has other limitations as well. For maximum effectiveness, it must be used within 72 hours after intercourse, and it doesn’t work as well among women taking some seizure medications or St. John’s wort.

That said, the physical side effects of Plan B are relatively minor; they include nausea, vomiting, headache and breast tenderness. Among women who do become pregnant after taking Plan B, there has been no evidence of altered growth or development of the fetus. There is also a low likelihood of birth defects. However, Plan B’s biggest downside is that it just doesn’t work very well. Plan B may give a false sense of security that a pregnancy won’t occur, so women should understand that they have other choices for emergency contraception.

The prescribed medication ulipristal acetate (Ella) has an efficacy rate of about 66.7 percent and can delay ovulation by five days. Further, the drug has been used in Europe for many years and has been FDA-approved in the United States since 2010. The side effects are similar to those of Plan B.

The most effective form of emergency contraception is the insertion of a copper intrauterine device (IUD) by a doctor. This is 95 percent effective at preventing pregnancy, and in a study of 1,013 women who had this device placed in the first five days after intercourse, the pregnancy rate was 2 in 1000.

Of course, many doctors don’t provide the copper IUD, and one could argue that a woman may not be able to see her doctor in a timely enough fashion to get an IUD or other form of emergency contraception. Some women may even be embarrassed to see a doctor about emergency contraception.