Deoxygenated fetal blood passes through umbilical arteries to the placenta. Abnormal development of the placenta leads to poor placental perfusion. Reduced blood flow to the placenta (placental hypoperfusion) is a key feature of the process. TSCs were observed because they reflect the initial cells that develop in the fetal placenta. Vaginal examination is avoided in known cases of placenta previa. Infection through the placenta during pregnancy is also possible. The exact cause of placenta previa is unknown. It is used to check the function of the ovaries, placenta, adrenal glands. Nonylphenol has also been shown to affect cytokine signaling molecule secretions in the human placenta. TF is also abundant in tissues of the lungs, brain, and placenta. The blood pressure decreases when passing through the placenta. This has rendered traditional classification of placenta previa obsolete. They ultimately restricted its use to expelling the placenta or stopping hemorrhage. The trophoblast gives rise to the placenta. An obstetrician may need to divide the anterior lying placenta.