Levonosterone is a widely used emergency contraceptive.
A widely used emergency contraceptive pill is more effective when taken in conjunction with anti-inflammatory drugs, a clinical trial has found.
Levonosterone is one of the cheapest and most widely used emergency contraceptives in the world.However, the drug is only effective until eggs are released from the ovaries.One study found that taking the drug within 49 to 72 hours of unprotected sex was only 58 percent effective in preventing pregnancy.
Anti-inflammatory drugs usually work by inhibiting prostaglandins, a hormone-like chemical that affects reproductive processes such as ovulation and fertilization.Kristina Gemzell Danielsson of the Karolinska Institute in Sweden suspects the drugs could further reduce the likelihood of unwanted pregnancies.
To verify this, Gemzell Danielsson and colleagues conducted a randomized experiment.The trial, conducted at a family planning clinic in Hong Kong, involved 860 women who were required to have emergency contraception within 72 hours of unprotected sex between August 2018 and 2022.Participants did not include any transgender or non-dual gender groups.
Half of the participants took levonorepine and piroxicam, an anti-inflammatory drug used to treat arthritis, while the other half took levonorepine pregnancy and placebo.Neither participants nor healthcare professionals knew which participants were taking which drug.
The results showed that only one woman in the anti-inflammatory group was pregnant and seven in the placebo group had no difference in side effects.
According to the expected pregnancy model after unprotected sex, 95 percent of the anti-inflammatory group were prevented from conceiving, compared with 63 percent of the placebo group.
The experiment involved only women who did not take any hormonal contraceptives because the researchers wanted to explore the effects of the drugs on women who were most likely to have unwanted pregnancies.
Gemzell Danielsson said it was unclear how the anti-inflammatory drug would help prevent unwanted pregnancies."We know prostaglandins are important for reproductive processes, but more mechanisms are needed to determine what really happened," she said.
She hoped that the findings would have an immediate impact on the issuance of emergency contraceptives by health professionals.Piroxicam is cheap, widely available, and it's easy to prescribe along with levonolprogesterone, she said.
Gemzell Danielsson said piroxicam could also be effective in combination with another widely used emergency contraceptive, ulipristal, because it works in a similar way to levonosterone, but it has not yet been tested.
Judith Stephenson of University College London said the findings could lead to significant changes in clinical practice, but she hoped other studies would confirm the results."Although this experiment is well designed, it is only one experiment, so confirming these results in another study is reassuring," she said.”
She also stressed the importance of knowing whether the combination of drugs worked for people who occasionally missed out on routine contraceptives.
The researchers reported the findings in the August 16 issue of The Lancet.