Researchers have identified a crucial molecular key to healthy embryo implantation and pregnancy, in a study led by Cincinnati Children’s that could improve treatment of infertility and abnormal development of the placenta.

The scientists found that uterine expression of a gene called Wnt5a – a major signaling molecule in cell growth and disease – is also critical to healthy embryo implantation in the uterus. The study was published July 17 in Cell Reports. 

Research on mice showed that molecular signaling from Wnt5a, working with its co-receptors in the uterus, causes uterine implantation chambers – or crypts - to form at regular intervals. The signaling also helps direct embryos as they settle into the womb. The authors say disruption of appropriate uterine signaling leads to abnormal formation of the crypt and spacing of embryos.

“Proper implantation is important to healthy pregnancy, and it is not clearly understood what prompts embryos to move and implant within a uterine crypt with regular spacing,” says Sudhansu K. Dey, PhD, senior investigator and Director of Division of Reproductive Sciences at Cincinnati Children’s. “If something goes wrong at this stage, there could be adverse effects throughout the course of pregnancy – whether it is subfertility, infertility, restricted growth, miscarriage or preterm birth.”

Despite some differences in mouse and human implantation, signaling in embryo spacing could be clinically relevant, Dey says, because the embryo sometimes implants close to or on the cervix. That causes extensive bleeding that could endanger both mother and fetus.

The study is a continuation of research Dey and his team published in 2011 in Developmental Cell. It was funded in part by the National Institutes of Health and the March of Dimes. Collaborators included researchers from National Institute of Genetics in Japan, the University of California at Davis and the National Cancer Institute.