A Dutch trial meant to study whether sildenafil, otherwise known as Viagra, can prevent children from being born with low birth weight has been halted early amid a wave of tragic deaths. Nearly 100 pregnant women were given the drug during their pregnancy in the trial, and 11 babies later died.
The deaths are especially frightening, since the drug is seemingly already being given to expectant mothers around the world.
Sildenafil affects the body by dilating blood vessels, making it easier for blood to flow to wherever it’s needed. That attribute has made the drug a successful treatment for erectile dysfunction, but some doctors started speculating it could also help mothers with placentas that don’t easily provide blood (and nutrients) to developing foetuses.
The incurable condition, known as intrauterine growth restriction, leads to stunted growth in foetuses that is usually spotted 20 weeks into the pregnancy through an ultrasound. The benefits of maternal sildenafil had earlier been seen in animal trials.
According to The Guardian, the trial began in 2015 and was originally set to run until 2020. Three-hundred and fifty women were expected to be recruited from 10 hospitals across the Netherlands, with half receiving sildenafil and half given a placebo.
As of last week, when the trial was ended by an independent committee, 183 women had taken part, with 93 receiving sildenafil.
Of the babies born to these women, 17 developed lung problems, with 11 dying soon after birth as a result. The rate of health complications and deaths was lower in the control group, with only three children experiencing any similar lung issues and none dying from it.
There were 17 other deaths seen during the trial, but these were considered unrelated to the drug’s use and split about equally between the groups. There were also no positive effects on birth weight or other health outcomes in the treatment group.
“We wanted to show that this is an effective way to promote the growth of the baby. But the opposite happened. I am shocked. The last thing you want is to harm patients,” lead researcher Wessel Ganzevoort, a gynaecologist at the Amsterdam University Medical Center, told Dutch daily newspaper De Volkskrant.
Currently, it’s theorised the drug might have caused some babies to have high blood pressure, which could have restricted blood and oxygen flow to their lungs. The independent committee reviewing the trial found no signs of malfeasance or improper actions taken by the trial researchers.
The Dutch trial results are only the latest to suggest that Viagra might not be as useful for mothers as thought.
The result of a trial in the UK released last year found no beneficial effect of the drug, though it also reported no significant adverse effects.
A trial out of New Zealand published in March similarly found no effect on birth weight, though it did suggest a slightly higher survival rate for the children of women who took sildenafil.
The unexpected deaths have led to another sildenafil trial in Canada being temporarily shut down, Ganzevoort told De Volkskrant, after his team reached out to that study’s researchers with their results. But some doctors might already be giving the drug off-label to pregnant patients, based on early positive findings.
“Foreign colleagues let slip that they sometimes prescribed it, with good results,” he said. “I have experienced in my own consulting room that pregnant women asked for it. Whether they have ordered it via the internet? I do not know. Who can know.”
The danger might not be over for some of the women and their children in the Dutch trial. Fifteen women had been taking sildenafil during their pregnancy just as the trial was shut down last week. They have since stopped taking it, but they are still waiting to find out if the therapy had any adverse effects on their children.
[De Volkskrant, via The Guardian]