58 Obstetrics and Gynecology Board Review •••
❍ What is the average blood flow to the uterus at term?
Approximately 600 mL/min.
❍ Name the principal prostaglandins produced by the amnion and the decidua.
The principal prostaglandin of the amnion is PGE2. The principal prostaglandin produced by the decidua
is PGF2alpha.
❍ When the fetal vertex enters the pelvis, and what is the most common position?
Left occiput transverse.
❍ In what percentage of pregnancies are there a nuchal cord?
10% to 25%.
❍ After delivery, signs of placental separation may include?
A gush of blood, lengthening of the umbilical cord, and anterior-cephalad movement of the uterine fundus.
❍ What are the classifications that describe the changes that occur with placental separation?
Latent phase, contraction phase, detachment phase, and expulsion phase.
❍ What is the definition of the latent phase of placental separation?
The latent phase is defined as from the time of delivery until the initiation of contractions leading to separation.
❍ Describe the contraction phase of normal placental separation.
Contraction at the placental site myometrium.
❍ What occurs during the detachment phase?
As the result of contraction of the myometrial insertion site, the placenta is sheared off the uterus.
❍ How is the expulsion phase defined?
The phase is defined as when the placenta is extruded from the uterus into the vagina.
❍ What is the average length of the third stage of labor?
<10 minutes, 90% within <15 minutes, and 97% within 30 minutes.
❍ What complication is associated with increase in duration of the third stage of labor?
Postpartum hemorrhage.
❍ Name the two approaches for the management of the third stage of labor.
Expectant and active.
❍ Expectant management is defined as?
Spontaneous delivery of the placenta without the use of pharmacologic agents or physical traction of the cord.