280 Obstetrics and Gynecology Board Review •••
❍ What is the source of an abdominal pregnancy?
It is thought that most abdominal pregnancies were tubal abortions.
❍ What is the appropriate treatment for an abdominal pregnancy?
Surgical removal of the fetus at the time of diagnosis is advised to prevent possible fatal hemorrhage. If possible the
placenta should be removed; however, if it is adherent to vital structures or cannot be completely removed, it may
be left to absorb over time.
❍ What is an interstitial pregnancy?
A pregnancy implanted at the proximal segment, interstitial portion of the fallopian tube, which is embedded
within the muscular wall of the uterus.
❍ How common are interstitial pregnancies?
They account for only 2% to 4% of tubal pregnancies.
❍ What are the risk factors for interstitial pregnancy?
Risk factors are the same as for other tubal pregnancies. However, ipsilateral salpingectomy is a risk factor specific
for interstitial pregnancy.
❍ What is the mortality rate of interstitial pregnancies?
2.5%, or seven times the rate of ectopic pregnancies in general
❍ What is the definition of a cornual pregnancy?
A pregnancy implanted in the horn of a bicornuate uterus.
❍ What is a hysterotomy scar pregnancy?
A pregnancy implanted at the previous hysterotomy (cesarean) scar.
❍ What is the incidence of hysterotomy scar pregnancy?
6% of ectopic pregnancies among women with a prior cesarean delivery, 2% of all ectopic pregnancies.
❍ Is the incidence of hysterotomy scar pregnancies related to number of previous cesarean deliveries?
No. Implantation occurs because the embryo migrates through a defect within the scar.
❍ How frequent are heterotopic pregnancies?
About 1/4000 to 1/8000 pregnancies. The incidence increases to about 1/100 with assisted reproductive
technologies.
❍ In a heterotopic pregnancy, how often will the intrauterine pregnancy survive after surgery for the ectopic
pregnancy?
About two-thirds of the intrauterine pregnancies survive following salpingectomy.