referred to as the “gate-keeper to the fetus.” Careful examination of the placenta, its membranes,
and the umbilical cord can prove to be a valuable aid in the diagnosis and treatment of the
neonate. Gross examination of the placenta takes five minutes, and more sophisticated examination
should be considered when there is poor pregnancy outcome, recognizable malformations or
abnormalities, multiple gestation, extremes of amniotic fluid volume, severe intrauterine growth
retardation, short umbilical cord (< 32 cm), and profound acidemia.
The maternal surface of the placenta (decidual plate) is soft, spongy and dark red; and the fetal surface (chorionic plate) is shiny and steel blue to gray.
The placenta, membranes, and umbilical cord weigh approximately 400 to 600 g at birth.
Abnormalities in structure can result in an inefficient transport of oxygen and nutrients to the developing baby. Despite this importance, it is one of the least understood and investigated human organs.
are of nearly equal size and this occurs in about 1% of deliveries. Note that the lobes are separated by membranes. The umbilical cord may insert into one or other lobe, or may insert between the two.
Its clinical significance is uncertain but it appears to be associated with a high incidence of both ante and postpartum bleeding. The fetus is often small for gestational age.
due to nonimmune causes.
by either the umbilical cord or by placental tissue. If tearing of these unsupported vessels occurs
before or during delivery, it can result in massive fetal blood loss.
of vigorous fetal activity. It is associated with about 10% of stillbirths. The knots must be very tight to obstruct blood flow. At the site of a long standing knot, such as in this fetus, there is a loss of Wharton’s jelly and a constriction of umbilical vessels. Wharton’s jelly probably prevents umbilical cord blood vessel compression by diffusing the pressure exerted by knots. The jelly is also slippery and this makes it difficult to maintain a knot.