Abdominal ectopic pregnancy

Abstract

An ectopic pregnancy (EP) accounts for 1-2% of all pregnancies, of which 90% implant in the fallopian tube. An abdominal ectopic pregnancy (AEP) is defined as an ectopic pregnancy occurring when the gestational sac is implanted in the peritoneal cavity outside the uterine cavity or the fallopian tube. Implantation sites may include the omentum, peritoneum of the pelvic and abdominal cavity, the uterine surface and abdominal organs such as the spleen, intestine, liver and blood vessels. Primary abdominal pregnancy results from fertilisation of the ovum in the abdominal cavity and secondary occurs from an aborted or ruptured tubal pregnancy. It represents a very rare form of an EP, occurring in <1% of cases. At early gestations, it can be challenging to render the diagnosis, and it can be misdiagnosed as a tubal ectopic pregnancy. An AEP diagnosed >20 weeks' gestation, caused by the implantation of an abnormal placenta, is an important cause of maternal-fetal mortality due to the high risk of a major obstetric haemorrhage and coagulopathy following partial or total placental separation. Management options include surgical therapy (laparoscopy±laparotomy), medical therapy with intramuscular or intralesional methotrexate and/or intracardiac potassium chloride or a combination of medical and surgical management. The authors present the case of a multiparous woman in her early 30s presenting with heavy vaginal bleeding and abdominal pain at 8 weeks' gestation. Her beta-human chorionic gonadotropin (bHCG) was 5760 IU/L (range: 0-5), consistent with a viable pregnancy. Her transvaginal ultrasound scan suggested an ectopic pregnancy. Laparoscopy confirmed an AEP involving the pelvic lateral sidewall. Her postoperative 48-hour bHCG was 374 IU/L. Due to the rarity of this presentation, a high index of clinical suspicion correlated with the woman's symptoms; bHCG and ultrasound scan is required to establish the diagnosis to prevent morbidity and mortality.

Keywords: Emergency medicine; Obstetrics and gynaecology.

Figure 1

Transvaginal ultrasound scan showing a lesion measuring 42×38 mm towards the midline of the pelvis. The lesion contained a cyst that appeared to contain an echogenic focus within, measuring 16 mm in diameter.

Figure 2

Repeat transvaginal ultrasound scan showing a crown-rump length (CRL) of 16.5 mm, suggesting a gestation of 8+1 weeks.

Figure 3

A mass extending from the pouch of Douglas and right pelvic sidewall in close proximity to the ovary was observed. It measured 4×3 cm in diameter.

Figure 4

A mass was observed extending from the right pelvic sidewall.