Umbilical cord:

1. What if there is only one artery?

A single umbilical artery has an incidence around 1% of all placentas, but it is more common in stillbirths, abortions, and neonatal deaths. Serious congenital anomalies occur in 15 to 30% of infants with single umbilical artery.

2. What does a very short or long cord mean (what governs the length of the cord)?

Neurologic function of the fetus governs fetal movement and cord length. Increased neuromuscular activity (increased fetal movement) results in an overly long cord, while decreased fetal activity may result in a short cord.

A long cord (>70 cm) may become wrapped around a fetal part (e.g., nuchal cord) or become knotted, though this is not common. A short cord (<30 cm) could interfere with delivery and be associated with anterior abdominal wall defects, but again only rarely.

3. What if the cord attaches peripherally into the membranes?

Such a "velamentous" insertion could predispose to rupture or obstruction at the time of delivery, though this is not common.

Fetal surface and fetal membranes:

1. What if there is yellow-green staining or opacification?

A yellow-green or green discoloration to the fetal surface or membranes suggests that meconium was released as a result of intrauterine stress. This also implies that the baby may have aspirated some of this meconium!

2. Why should the dividing membranes on a twin placenta be examined?

Examination of the dividing membranes can help to give an indication of the zygosity (monoamnionic-monochorionic is more likely with monozygous twins, diamnionic-dichorionic implies dizygous twins).

Maternal surface:

1. What do missing cotyledons imply?

A missing portion of placenta may still be in the mother's uterus (so-called "retained products of conception").

2. What does a blood clot mean?

There is normally a small amount of clotted blood adherent to a placenta, but a large clot, particularly if it indents the maternal surface, suggests an abruptio placenta.

3. What if the placenta is large and hydropic?

Hydrops may be immune (erythroblastosis fetalis fro Rh or other red cell immunization) or non-immune (usually from congenital infection such as with the TORCH agents).

4. What is an infarct and what does it mean?

A blockage of maternal blood flow could lead to an area of ischemia and result in an infarct. The placenta is normally large enough that a significant portion of the placenta must be infarcted before the fetus dies.