"For pregnant mammals, Viagra can enhance the supply of nutrients from the mother to the fetus via utero-placental blood flow," he said.

The study revealed Viagra increased the blood supply to the fetus in female sheep, supplying amino acids - a major fuel for fetal growth. Approximately 60 ewes were mated to rams at the Texas A&M University Sheep Center. Pregnant females were randomly selected and treated with or without sildenafil citrate.

Results of the study indicated long-term use of Viagra enhanced fetal weight in both "adequately fed and nutrient-restricted female sheep." Greater concentrations of amino acids and polyamines in fetal blood and placental fluids were found, leading the researchers to suggest that Viagra alters the trafficking of nutrients from the female sheep to the fetus.

It was also observed that Viagra did not affect changes in maternal weight, body condition score, maternal liver mass or muscle weight, Wu said.

"We were surprised that Viagra enhanced ovine fetal growth under the conditions of either adequate or inadequate maternal intakes of nutrients from the diet. The results of our study indicate that augmenting systemic blood flow may be a novel and effective strategy to prevent fetal growth retardation in humans and livestock species without affecting maternal health."

Wu said the team would like to extend its research into future studies involving other mammalian species, including pigs, cows and humans.

Source: Texas AgriLife Research and Texas A&M AgriLife Communications