The emergency contraceptive levonorgestrel is much more effective at preventing pregnancy if the anti-inflammatory drug piroxicam is taken at the same time
By Jason Arunn Murugesu
16 August 2023
Levonorgestrel is a widely used emergency contraceptive pill
Kristoffer Tripplaar / Alamy Stock Photo
A widely used morning-after pill is far more effective when taken alongside an anti-inflammatory drug, a clinical trial has found.
Levonorgestrel is one of the cheapest and most widely used emergency contraceptives in the world. But the drug only works before an egg is released from one of the ovaries. One study found that the drug is only 58 per cent effective at preventing pregnancies when taken 49 to 72 hours after unprotected sex.
Anti-inflammatory drugs generally work by inhibiting prostaglandins, chemicals with hormone-like effects that also play a role in many processes in reproduction such as ovulation and fertilisation. Kristina Gemzell-Danielsson at the Karolinska Institute in Sweden suspected that these drugs could further reduce the likelihood of unwanted pregnancy.
Advertisement
To test this, Gemzell-Danielsson and her colleagues conducted a randomised trial involving 860 women who requested emergency contraception within 72 hours of unprotected sex at a family planning clinic in Hong Kong between August 2018 and 2022. The participants didn’t include any transgender or non-binary people.
Half the women were given levonorgestrel and piroxicam, an anti-inflammatory drug used to treat arthritis, while the other half received levonorgestrel and a placebo pill. Neither the participants nor the healthcare professionals knew which participants received which treatment.
Just one woman became pregnant in the anti-inflammatory drug group, whereas seven women became pregnant in the placebo group. There were no differences in side effects between the two groups.