It's known for its, er, uplifting properties, but now scientists are looking into another use for Viagra – to help boost the growth of underweight unborn babies.
Doctors are to give more than 120 women carrying extremely low-growth babies regular doses of sildenafil citrate, a generic version of the anti-impotence drug Viagra, during their pregnancy.
A previous study found that Viagra boosted blood flow to the placenta, which in turn promoted baby growth.
The results will then be compared with those from a similar group of women given an identical looking dummy tablet.
Around 600 babies a year in the UK are stillborn because of a pregnancy disorder called pre-eclampsia. The arteries feeding the placenta do not widen enough to deliver all the blood the baby needs.
But during tests foetal deaths dropped sharply in pregnant mice given Viagra.
The drug helps by relaxing muscles in the artery walls and allowing more nutrient-rich blood to pump through.
Dr Kate Groom, who is leading the research at the University of Auckland, said: "If we can enhance foetal growth and delay delivery, we will improve babies' survival rates and reduce the many complications that can lead to life-long disability or disease."