Funding outcome

In Canada, advanced age pregnancies (AAP) are becoming more common. AAP is when a pregnant person is older than 35 years and this increases the risk of having pregnancy issues like preterm birth or miscarriage. More needs to be done to understand why AAPs are at a higher risk. A tissue layer called the endometrium covers the inside of the uterus. During pregnancy, the endometrium changes into the decidua. This process is called decidualization. The decidua brings nutrients to the fetus, protects the fetus, and allows the placenta to develop. A key feature of decidualization is blood vessel remodelling where the blood vessel network grows and expands. This allows blood flow to the placenta. Endothelial cells are the cells that line the blood vessels. These drive decidualization. Defects or delays in decidualization can lead to severe pregnancy issues. An important controller of decidualization is when progesterone, a hormone that increases during pregnancy, binds to progesterone receptors. Studies in mice have found that ~25% endothelial cells have progesterone receptors. Even though there are not many of them, when progesterone receptor expressing endothelial cells are lost pregnancies are less successful. We have initial data suggesting there are fewer progesterone receptor expressing endothelial cells in AAP compared to young human decidua. We propose that these decreases may lead to poor blood vessel remodelling and decidualization in AAP. In this project we will collect endothelial cells from human decidua to confirm whether there are changes in the number of progesterone receptor expressing endothelial cells in young vs. AAP decidua. We will also develop a method to separate progesterone receptor expressing cells from other endothelial cells. In the far future, these findings could be used to develop treatments that decrease the complication risks associated with AAP.