Searching for the role of hemoglobin in female reproductive health

Hemoglobin is known mostly as a component in red blood cells that carries oxygen through the body. But it exists outside of red blood cells, and Washington State University researchers have found it in female reproductive tissue. The problem is, they don’t know why it’s there, what it does, or its role in a healthy pregnancy.

Portrait photo of Pru
Jim Pru

Solving that mystery is the goal of new research being supported by a recent $450,000 grant WSU Animal Sciences professor Jim Pru received from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, an institute within the National Institutes of Health (NIH).

“We’re going to test the function of uterine-derived hemoglobin to determine if it is essential for pregnancy and then evaluate what role it plays in the establishment and maintenance of pregnancy,” said Pru, a molecular reproductive biologist specializing in women’s reproductive health.

He said finding this answer in mice could lead to breakthroughs in humans and domestic livestock.

“We think that the uterine-derived hemoglobin is regulating oxygen near the developing embryo in the uterus,” Pru said. “Evidence suggests that this hemoglobin also serves as a scavenger with anti-oxidant functions.”

Antioxidants prevent damage to DNA in cells, something vitally important in an embryo, he said. Any defects to DNA of an embryo are replicated throughout that embryo’s development. Too much damage can lead to congenital birth defects or even miscarriage.

In humans, most miscarriages occur before an embryo implants into the mother’s uterus and a placenta develops. The placenta forms around 5-6 weeks of gestation and is the primary way a fetus receives nutrients from the mother.

Before the placenta develops, an embryo still needs nutrients and oxygen to grow and survive. The newly discovered uterine-derived hemoglobin may be helping with that as well, Pru said.

“One thing that happens in pregnancy is that the uterus becomes highly vascularized with an increased blood supply,” he said. “Mom is bringing nutrients and removing waste and we think this hemoglobin is an essential part of this process.”

Pru isn’t a medical doctor, he’s a scientist looking to solve problems at the molecular level. But he said if his team gets the results they expect, it could have benefits for the 15 percent of human couples that are infertile.

“Perhaps the greatest practical impact of this research would come in the in vitro fertilization clinic,” he said. “We still haven’t mastered conditions for in vitro fertilization, a process that naturally occurs in the oviduct. Optimizing in vitro fertilization conditions will help pregnancy outcomes.”