Pfizer Thursday insisted its anti-impotency Viagra drug was not used in a Dutch study seeking to help pregnant women whose babies were not growing properly, halted after 11 infants died.
"Pfizer was never involved in this study and neither supplied drugs or funding to it," the company said in a statement sent to AFP.
Amsterdam University Medical Centre, which carried out the research along with 10 other hospitals in the Netherlands, announced Monday the study had been stopped after the deaths of the babies, and after others developed lung disease having been born prematurely.
It said 183 women had been involved in the trial launched in 2015, in which 93 were given the generic anti-impotency drug sildenafil. The other 90 women were given a placebo.
None of the mothers were affected by the drug.
But out of the 93 women using the drug, 19 babies died, 11 of them possibly due to a form of high blood pressure in the lungs which may be linked to the drug.
The university said in a tweet that sildenafil "is also known as Viagra" but in an updated statement stressed "neither Pfizer Viagra or Pfizer Sildenafil were used as medicines in this study".
"The results of the study... are extremely sad and disappointing for the people involved and the researchers," Pfizer added.
It stressed that Viagra is a drug to treat adult erectile dysfunction and its safety and effectiveness had been proven in more than 15,000 patients.
The Dutch scientists had hoped sildenafil's properties in dilating blood vessels could help promote a better flow of blood into the placenta and "stimulate the growth of the unborn child" whose development had been retarded in the mother's womb, the hospital said in a statement.
Explore further: Dutch halt Viagra in pregnancy trial after 11 babies die