Maternal tissue refers to the tissues and cells originating from the mother during pregnancy. A key component is the decidua, which is derived from the endometrium (the lining of the uterus). The decidua is further divided into three parts:
- Decidua basalis: Located deep at the implantation site of the embryo.
- Decidua capsularis: Covers the implantation site.
- Decidua parietalis: Encompasses the remaining uterine lining.
Beyond the decidua, maternal tissue also encompasses other uterine tissues and potentially cells circulating in the mother's bloodstream. Research indicates that fetal cells can transfer to maternal tissues during pregnancy, a phenomenon called fetal microchimerism. These fetal cells can persist in the mother's body for years and may even contribute to maternal tissue regeneration or have other, yet to be fully understood, consequences. Studies have shown the detection of these fetal cells, exhibiting characteristics of various cell types (epithelial, leukocyte, hepatocyte), in diverse maternal tissue samples. The transfer of fetal cells may occur through cell fusion or transdifferentiation.
The maternal tissue plays a crucial role in supporting fetal development by providing nutrients and oxygen. Changes in maternal tissues, such as growth in adipose tissue, also occur during pregnancy to accommodate the demands of the growing fetus. Conversely, research is ongoing into the role that fetal stem cells play in maternal tissue regeneration in response to injury.
