Scientists got 9 women to try an on-demand contraceptive pill just before sex to prevent pregnancy, and they say it works

• Scientists tested a birth control pill you take right before penetrative sex in a small preliminary study.
• Nine women took the pill while ovulating. It stopped eight of their ovulation cycles, which is considered the peak time to conceive.

An on-demand birth control pill could soon be a reality.

According to preliminary research published today in the journal BMJ Sexual & Reproductive Health, a pill that combines two existing medications has the potential to prevent pregnancy if a person takes it right before sex.

In a small study of nine women who were ovulating, scientists gave each a pill that contained ulipristal acetate and meloxicam. Ulipristal acetate is the active drug in prescription emergency contraception. Meloxicam is an non-steroidal anti-inflammatory drug (NSAID) that can reduce pain and swelling. It's commonly found in over-the counter pain relievers like ibuprofen, but researchers have also found it can disrupt a person's ovulation cycle.

Research suggests a person has a greater chance of conceiving while ovulating, so the researchers wanted to see if this drug combination could work during that particular phase of the menstrual cycle. To do that, the researchers gave women between 18 and 35, who were considered healthy with normal menstrual cycles, the pill they were testing.

They found six of the nine women they studied experienced ovulation disruption, and 8 of the women met the criteria for incomplete ovulation, meaning an egg didn't drop from their ovaries into their uterus, so they can't become pregnant.

According to the researchers, their findings suggest this new pill is the best-known medication for stopping successful ovulation, but more extensive studies and safety tests should be done.