October 19, 2011

Sheep study could shed light on human pregnancies

Florida native sheep, like those used in the study

In human infants, traits like reduced birth weight and late-preterm birth are associated with health problems later in life. In fact, a recent study in the journal Pediatrics showed a link between low birth weight and an increased risk of developing autism. To better understand human health, many scientists want to know more about what happens inside the womb.

To aid those studying human pregnancies, a group of scientists from Texas A&M University and the University of Florida recently published data showing the stages of sheep fetal and placental development. This research, published online in the Journal of Animal Science, provides crucial background information for researchers hoping to use sheep development to study human growth.

“Sheep have turned out to be a useful model because of the stages that the pregnancy goes through,” said study co-author Dr. Fuller Bazer, an animal scientist from Texas A&M University.

There was no control group or experimental group in this study. Bazer and his colleagues simply wanted to analyze the stages of sheep pregnancy under typical lab conditions.

“Other scientists can use this as baseline data if they’re working with sheep,” Bazer said.

By studying the uteri of pregnant ewes, Bazer and his colleagues found that the sheep placenta goes through the same stages as the human placenta. The placenta grows rapidly during the first stages of pregnancy, allowing nutrients and gases to pass through as the fetus grows later on. By looking at the condition of the uterus at different points of pregnancy, the researchers discovered that volumes and concentrations of nutrients like calcium, potassium and protein changed over time. The researchers also found changes in the levels of sex steroids, glucose and amniotic fluid.

Understanding normal fetal development can help scientists and sheep producers spot problems caused by undernutrition, overnutrition and environmental stress, said Bazer. This information could also help humans stay healthy during pregnancy. Bazer explained that teenage girls have a higher risk of giving birth to small-for-date babies. Perhaps sheep studies could explain that trend. Sheep studies could also help scientists understand why babies born to overweight mothers are more prone to diabetes.

Bazer explained that this study is also significant because it was written to honor the memory of Dr. Donald H. Barron, a “founding father” of fetal-placental physiology. Barron served as a mentor to Bazer, and he helped collect samples for this study.

This study was titled “Growth and development of the ovine conceptus.” It can be read in full at http://jas.fass.org.

Media Contact: Madeline McCurry-Schmidt

MadelineMS@assochq.org / 217-239-3321