Abdominal pregnancy

Clinical History

A woman arrived at the emergency room with sudden onset abdominal pain of two hours duration. The patient had no previous diseases or surgery. She had five months of amenorrhoea before the ED visit.
In evaluation, we observed hypo-tension and diffuse abdominal pain. Analytic evaluation found anaemia and a positive pregnancy test.

Imaging Findings

o Haemoperitoneum
o Normal size uterus and normal adnexal
o Dead fetus with biometry consistent with 23 weeks of gestation

Discussion

Background: Abdominal pregnancy is a pregnancy that has implanted in the peritoneal cavity. The incidence is 1 per 10, 000 births and 1.4 percent of all ectopic pregnancies. [1] Potential sites include the omentum, pelvic sidewall, broad ligament, posterior cul-de-sac, abdominal organs (e.g. spleen, bowel, liver), large pelvic vessels, diaphragm, and the uterine serosa. [2]
Risk factors for abdominal pregnancy include tubal damage, pelvic inflammatory disease, endometriosis, assisted reproductive techniques, and multiparity. [1, 2]

Clinical perspective:
Because of the variable location in abdomen, abdominal pregnancy is associated with many signs and symptoms. Unlike tubal ectopic pregnancies, abdominal pregnancies may remain undetected until an advanced gestational age, sometimes until term. [1]

Vaginal blood loss can occur in response to hormonal changes of pregnancy. Some women present with an acute abdomen and shock due to severe intraabdominal haemorrhage from placental separation or rupture of maternal blood vessels or viscera. Other rare presentations are possible such as bowel obstruction and formation of fistulae. [3]

Imaging perspective:
All women of reproductive age with vaginal bleeding/menstrual abnormalities or abdominal pain should be tested for pregnancy. When pregnancy is confirmed, one should check for location of the pregnancy (intrauterine or extra uterine) by ultrasound. [2]
The classic ultrasound finding for abdominal pregnancy is the absence of myometrial tissue between the maternal bladder and the pregnancy. An empty uterus may be visualised. Other findings suggestive of the diagnosis include poor definition of the placenta, oligohydramnios, and unusual fetal lie. [1]
Computed tomography and magnetic resonance imaging can be useful for confirming the diagnosis, distinguishing anatomic relationships and potential vascular connections, and assessing placental adherence. [1]

Outcome: An assessment of outcome is difficult to determine since most of the literature results stem from case reports. However, maternal death, resulting from haemorrhage, can reach 20% in many cases. [1, 2] Fetal deformations and perinatal death occur more often than maternal death. There are some fetal abnormalities described that include facial and/or cranial asymmetry, joint abnormalities (e.g., talipes equinovarus), hypoplastic limbs, and central nervous system malformations. [2]

Differential Diagnosis List

Final Diagnosis

Abdominal pregnancy

URL:	https://www.eurorad.org/case/10367
DOI:	10.1594/EURORAD/CASE.10367
ISSN:	1563-4086