In laboratory experiments, early-stage human embryos donated from couples after IVF treatment successfully implanted into the engineered lining and began to churn out key compounds, such as the hormone that results in a blue line on positive pregnancy tests. The approach allowed scientists to eavesdrop on the chemical chatter that arises between the embryo and the womb lining as it embeds and begins to be nourished in the first weeks of gestation.
The simulation made it possible to appreciate how a human embryo does not merely adhere to the uterine lining, but actively inserts itself. "We observe that the embryo pulls on the uterine matrix, moving and reorganizing it," explained Amélie Godeau, coauthor of the research, which was published in Science Advances. These movements could explain the pain some women report days after fertilization.