Male pill
© Shutterstock / g-stockstudioScientists have edged one step closer to creating a male 'pill', new research suggests
Scientists have edged one step closer to creating a male pill, new research suggests.

Thirty hours after infusing male macaques with a compound known as EP055, their sperm were unable to move, a study found.

Lead author Dr Michael O'Rand, from the University of North Carolina, said: 'Simply put, the compound turns-off the sperm's ability to swim, significantly limiting fertilization capabilities.'

None of the monkeys suffered side effects, which is thought to be due to EP055 having no effect on male hormones, according to the researchers.

Most female birth-control pills contain a mix of the hormones oestrogen and progesterone, which can cause weight gain, erratic moods and nausea.

In addition, all of the monkeys' sperm were moving as normal within three weeks, suggesting the treatment is reversible, the research adds.

Currently, male contraception is largely limited to condoms, which can fail up to 18 percent of the time if worn incorrectly, or vasectomies, which are expensive and difficult to reverse.

Complete recovery after 18 days

EP055 binds to the protein EPPIN, which is present on surface of sperm.

Within six hours of infusion, the monkeys' sperm mobility was reduced by around 20 percent.

Speaking of the findings, study author Dr Mary Zelinski added: 'At 18 days post-infusion, all macaques showed signs of complete recovery, suggesting that the EP055 compound is indeed reversible.'

Sperm mobility began to improve after around three days.

The researchers add it is unclear when the contraception may be available for human use.

They are testing EP055 in pill form and plan to investigate it effectiveness at preventing pregnancy in an animal study.

How the research was carried out

The scientists infused four male macaques with a 75-80mg/kg dose of EP055.

After a recovery period, they then administered a 125-130mg/kg dose.

The findings were published in the journal PLOS ONE.

Birth-control pills increase women's risk of stroke

This comes after research released last month suggested oral contraceptives increase women's risk of stroke.

Birth-control pills raise a woman's likelihood of suffering from an ischemic stroke, which occurs when an artery to the brain is blocked and makes up around 85 percent of cases of the life-threatening condition, a study found.

The researchers, from Loyola University, Chicago, wrote: '[Among] women with other stroke risk factors, the risk seems higher and, in most cases, oral contraceptive use should be discouraged'.

Such contraceptives do not raise the risk of hemorrhagic strokes, which are caused by bleeding in the brain, the research adds.

Birth-control pills, patches and jabs are thought to raise the risk of artery blockages by making blood more likely to clot.

The researchers stress, however, the risk is low among women without any risk factors for clotting, such as high-blood pressure and smoking.

Most women have tried at least one hormonal contraceptive in their lives. In the US, nearly 37 percent of women are currently using birth control.

Stroke is the third leading cause of death in women in the US, with 55,000 more females suffering than men every year.