Nonfallopian-Tube Ectopic Pregnancy
Ectopic implantation of the fertilized egg in the ovary is rare. The recent increased incidence is likely due to im-proved imaging modalities. Risk factors are similar to those for tubal pregnancies. Diagnosis is based on the classical sonographic description of a cyst with a wide echogenic outer ring on or within the ovary.
Also termed cornual pregnancy, interstitial pregnancies implant in the proximal tubal segment that lies within the muscular uterine wall. Swelling lateral to the insertion of the round ligament is the characteristic anatomic finding. A pregnancy that implants in the cornual segment of the tube tends to present several weeks later in pregnancy, be-cause the muscular cornu of the uterus is better able to expand and accommodate an enlarging pregnancy. As a result, rupture of a cornual (isthmic) pregnancy typically occurs between the eighth and sixteenth gestational weeks, and is often associated with massive hemorrhage, frequently requiring hysterectomy. Mortality rates are quoted as high as 2.5%.
pregnancy occurs in 1 in 9000 to 12,000 preg-nancies, when
the ovum implants in the cervical mucosa below the level of the histologic
cervical internal os. A risk factor unique to cervical pregnancy is a history
of dilation and curettage, seen in nearly 70% of cases. Two diagnos-tic
criteria are necessary for confirmation of cervical preg-nancy: (1) the
presence of cervical glands opposite the placental attachment site, and (2) a
portion of or the en-tire placenta must be located below either the entrance of
the uterine vessels or the peritoneal reflection on the ante-rior and posterior
uterine surface. Medical management can be used if the previously described
criteria are met.
pregnancy (coincident or combined preg-nancy) is the
coexistence of an ectopic and intrauterine pregnancy. The incidence was
previously estimated to be 1 in 30,000 pregnancies figuring incidences of
dizygotic twinning and ectopic pregnancy of 1% each. As a result of assisted
reproduction, however, the rate of heterotopic pregnancies has increased to 1
in 100 pregnancies. Mech-anisms that have been proposed to explain this
include: (1) hydrostatic forces delivering the embryo into the cor-nual or
tubal area; (2) the tip of the catheter directing trans-fer towards the tubal
ostia; or (3) reflux of uterine secretions leading to retrograde tubal
implantation. In addition to the option of surgical management of the ectopic
pregnancy while attempting to not disturb the intrauterine pregnancy, medical
therapy in which potassium chloride can be in-jected into the pregnancy sac is
is contraindicated due to potential detrimental effects on the normal
The estimated incidence of abdominal pregnancy ranges from 1 in
10,000 to 1 in 25,000 live births. Abdominal pregnancies may result from primary
implantation onto the peritoneal surface or secondary implantation via tubal
rupture or tubal abortion. Physical findings and symptoms are widely variable,
depending on gestational age and site of implantation. Diagnosis is confirmed
primarily by ultra-sonography.
Abdominal pregnancy is usually
discovered long be-fore fetal viability and removal of the pregnancy is the
mainstay of therapy. Survival of the fetus occurs in only 10% to 20% of cases;
up to one-half of those surviving have significant deformity. The patient is
given the option of continuing the pregnancy to fetal viability with opera-tive
delivery, or operative termination of the pregnancy at the time of diagnosis.
In either case, removal of the pla-centa is usually not attempted because of the
risk of un-controllable hemorrhage.