Studies suggest that an accepted downside to the morning-after pill is that out of 100 women who use the emergency contraception, two will still become pregnant—but that statistic may soon be a thing of the past.
Researchers from the University of Hong Kong may have found a way to make these pills even more effective: by combining them with a routine anti-inflammatory drug used to reduce pain from arthritis.
“This combination can be potentially put into routine clinical use to improve the effectiveness of emergency contraception,” lead researcher, Raymond Li, told Newsweek.
Plan B is the most popular morning-after pill in the U.S. It contains 1.5mg of a compound called levonorgestrel—a synthetic hormone similar to a one that normally peaks in the second half of the menstrual cycle called progesterone.
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This hormone prevents pregnancy by delaying ovulation. However, studies have shown that Plan B and similar pills are only effective if they are taken before ovulation takes place.
In a recent study, published in the Lancet on August 16, Li and his team set about investigating whether other processes could be targeted to reduce the risk of pregnancy after taking emergency contraception. And they found a potential contender.
Prostaglandins are hormone-like molecules involved in a range of bodily processes, including reproduction. According to co-author Kristina Gemzell-Danielsson, from the Karolinska Institute in Sweden, prostaglandins are involved in ovulation, fertilization and embryo implantation. Therefore, preventing the production of these molecules may help prevent pregnancy both before and after ovulation when taken in conjunction with contraceptives like levonorgestrel.
The anti-inflammatory drug, piroxicam, is thought to do just that. Conventionally, the drug is used to reduce pain in people with arthritis, but, theoretically, it could also help reduce the risk of pregnancy through this pathway.
To find out, Li and colleagues recruited a group of 836 women who required emergency contraception within 72 hours of having unprotected sex. Half of these women were given hormonal emergency contraception in combination with the anti-inflammatory drugs, while the other half were given contraception together with a placebo.
The likelihood of getting pregnant from unprotected sex without emergency contraception is roughly 4.5 percent, so for each of these groups, 19 women would have probably become pregnant if no contraception was taken.
For those who took levonorgestrel alone, only seven of these 19 expected pregnancies took place, resulting in a 63 percent success rate. However, among those who were given both drugs, only one of these 19 expected pregnancies took place, giving an efficacy of 95 percent.
“The levonorgestrel emergency contraceptive pill is one of the most popular choices of emergency contraception in many parts of the world, so finding out that there is a widely available medication which increases levonorgestrel’s efficacy when they are taken together is really exciting”, Sue Lo from the Family Planning Association of Hong Kong and co-investigator on the study, said in a statement.
Theoretically, drugs like piroxicam can cause stomach aches and peptic ulceration after prolonged use, but Li said that the team did not observe any of these side effects among the study’s participants.
It is important to note that this is a fairly small study, and exactly how piroxicam brings about these effects is still not entirely clear. However, it is an exciting step towards improving our ability to prevent unwanted pregnancies and to provide options for people who menstruate throughout their cycle.
The results may also not be applicable to all demographics: “These conclusions might not apply to all patients, as this study was limited by a specific population, with participants being mostly of Asian ethnicity and weighing less than 70 kg (154 pounds),” Erica Cahill from Stanford University School of Medicine, who was not involved in the study, said in a linked comment on the study.
“Given that levonorgestrel emergency contraception is less effective in people with obesity, the efficacy shown here might not be generalizable to patients with higher BMIs,” she wrote.
