Novel method to monitor blood flow in pregnant sows

Scientists developed new ultrasound method to monitor umbilical blood flow in the pig at multiple stages of pregnancy.

There is often large variation within a litter of piglets in the individual birth weight of piglets, with many litters having a “runt” piglet, which are at a permanent disadvantage compared to their normal-sized littermates, according to researchers at The Roslin Institute in the U.K.

The weight of pig fetuses within the same uterus varies substantially, even during early pregnancy, suggesting that the differences observed after birth could arise early in development, the announcement said. Can these differences in fetal size be attributed to differences in blood supply to fetuses during pregnancy?

A study led by Dr. Claire Stenhouse from The Roslin Institute describes a new, non-invasive method to monitor umbilical blood flow at multiple days of pregnancy in the sow to improve the understanding of pre-natal piglet growth.

According to the announcement, the team successfully developed a novel method to monitor umbilical blood flow within the same animal at multiple stages of pregnancy, which has not previously been possible in a non-invasive way in the pig.

They observed changes in fetal heart rate and umbilical blood flow that were associated with the stage of pregnancy, in a similar way to what is observed in humans.

They also reported interesting relationships between both the sex ratio of the litter and the weight of a fetus on umbilical blood flow, Roslin said. Intriguingly, the use of light maternal sedation in early pregnancy was found to decrease fetal weight in late pregnancy, which could have significant implications in both medical and veterinary practice.

“Understanding the mechanisms governing fetal growth has important applications for the pig industry. In this study, we have demonstrated that it is possible to monitor blood flow to fetuses throughout pregnancy in the pig in a minimally invasive way. It is hoped, with further optimization, it may be feasible to measure blood flow in the umbilical cord of growth-restricted piglets throughout pregnancy,” Stenhouse said. “This is also of great interest in humans, particularly in the context of use of sedatives during pregnancy and improving the understanding of intrauterine growth restriction.”

The study, which was funded by the U.K.’s Biotechnology & Biological Sciences Research Council, was published in the journal Reproduction, Fertility & Development. It was conducted by researchers at The Roslin Institute and the Centre for Reproductive Health at the University of Edinburgh.