The placenta

Abnormal placental development and function are widely recognized as having immediate consequences on the outcome of a pregnancy, and more recently to influence the lifelong health of the offspring. The development of the placenta starts from implantation, when the embryonic pole of the blastocyst enters into contact with the maternal uterine epithelium. The placenta provides the fetus with all essential nutrients, water, and oxygen, and a route for clearance of fetal excretory products, but it also produces a vast array of protein and steroid hormones and factors necessary for the maintenance of pregnancy. Placental-related disorders of pregnancy affect around a third of human pregnancies, primarily including miscarriages, pre-eclampsia, and fetal growth restriction. Placental and umbilical cord structural anomalies that are associated with perinatal complications can now be diagnosed from early in pregnancy with ultrasonography and the antenatal detection of anomalies such as placenta praevia and placenta accreta has a direct impact on the outcome of pregnancy.