Researchers described a rare case of primary abdominal ectopic pregnancy initially mistaken for gastroenteritis after a patient presented with persistent upper abdominal pain rather than the more typical lower abdominal pain or vaginal bleeding.
The case report, published in Medicine, detailed the laparoscopic diagnosis and management of an early abdominal ectopic pregnancy in a 25-year-old patient at approximately 5 weeks of gestation following ultrasound findings showing no intrauterine gestational sac or adnexal abnormality and contrast computed tomography (CT) imaging of the upper abdomen.
The patient, gravida 1 para 0, initially presented to a local hospital with mild left upper abdominal pain on March 30, 2025. Noncontrast CT showed a left upper abdominal lesion measuring approximately 21 mm × 19 mm × 10 mm, but contrast imaging was unavailable at that facility. She was diagnosed with gastroenteritis and treated with anti-inflammatory, acid-suppressing, and antispasmodic medications for 1 week without symptom relief.
Following amenorrhea, the patient had a positive urinary pregnancy test on April 6. Worsening left upper abdominal pain accompanied by nausea and vomiting prompted transfer to the reporting hospital the following day. Emergency ultrasound showed no intrauterine gestational sac, an 8-mm endometrium, and no bilateral adnexal abnormalities. Contrast CT demonstrated a vascular mass in the same upper abdominal location measuring approximately 46 mm × 40 mm × 56 mm. Serum human chorionic gonadotropin was 10,130 IU/L.
On admission, the patient had stable vital signs, localized left upper abdominal tenderness, no lower abdominal guarding or rigidity, no active vaginal bleeding, no cervical motion tenderness, and no palpable adnexal mass. She had conceived naturally and had no history of pelvic inflammatory disease, infertility treatment, chronic medical illness, tobacco use, or alcohol use.
Because magnetic resonance imaging (MRI) was not immediately available and cost constraints precluded private-facility MRI, clinicians proceeded with diagnostic laparoscopy. Surgery revealed approximately 300 mL of hemoperitoneum and a hematoma between the inferior border of the spleen and the descending colon surrounded by greater omentum with active bleeding. A 6 cm × 4 cm × 5 cm lesion containing products of conception was identified, while the uterus, ovaries, and fallopian tubes appeared grossly normal.
A gastrointestinal surgeon assisted with excision of the ectopic pregnancy lesion and partial omentectomy. Postoperative pathology confirmed abdominal ectopic pregnancy. The patient was discharged 5 days following surgery without complications, and serum human chorionic gonadotropin normalized to less than 5 IU/L within 1 month.
The researchers classified the case as primary abdominal ectopic pregnancy based on Studdiford criteria, which include normal-appearing fallopian tubes and ovaries, absence of a uteroperitoneal fistula, products of conception confined to the abdominal cavity, and sufficiently early gestation to reduce concern for secondary implantation following tubal nidation.
Abdominal ectopic pregnancy is rare, accounting for approximately 1% to 1.3% of ectopic pregnancies depending on classification methods cited in prior literature. The report noted that mortality associated with abdominal ectopic pregnancy has been estimated to be 7.7 times higher than that associated with tubal ectopic pregnancy.
The researchers also cited a review of 17 abdominal pregnancy cases in which only 29% were diagnosed prior to surgery, while approximately 70% were initially misdiagnosed as tubal ectopic pregnancy or unexplained intra-abdominal hemorrhage.
The report emphasized that abdominal ectopic pregnancy may be difficult to recognize because vaginal bleeding is less common than in tubal ectopic pregnancy and symptoms may mimic gastrointestinal disease. The researchers noted that transvaginal ultrasound combined with serum human chorionic gonadotropin monitoring remains the current diagnostic standard for ectopic pregnancy and that serum human chorionic gonadotropin levels greater than 2,000 IU/L without evidence of intrauterine pregnancy should raise strong suspicion for ectopic pregnancy.
The researchers noted that MRI may aid surgical planning in advanced abdominal pregnancy and that contrast CT helped identify the lesion in this case when MRI was unavailable. The report further highlighted the importance of considering ectopic pregnancy in reproductive-age patients with atypical abdominal symptoms and unexplained abdominal lesions on imaging.
Although this patient conceived naturally and had no history of infertility treatment, the researchers also highlighted assisted reproductive technology as a recognized risk factor for abdominal ectopic pregnancy and noted that some cases associated with assisted reproduction have been diagnosed despite very low or even normal human chorionic gonadotropin levels.
No standardized treatment protocol exists for abdominal ectopic pregnancy, according to the report. Although selected cases have been managed medically with methotrexate, the researchers stated that surgical resection is generally considered the standard treatment, with laparoscopy favored in appropriately selected early pregnancies. In this patient, expectant and medical management were not considered appropriate because active intra-abdominal bleeding was present.
The researchers additionally discussed management challenges in advanced abdominal pregnancies, particularly placental management. Reported approaches have included vascular embolization, leaving the placenta in situ for spontaneous or methotrexate-assisted resorption, and staged surgical removal in selected cases.
“Management of complicated EPs requires a multidisciplinary team involving experienced obstetricians, diagnostic radiologists and general surgeons to reduce surgical risks and prevent adverse maternal outcomes,” wrote lead study author Hong Xu, MBBS, of the Department of Gynecology, Suzhou Ninth People’s Hospital, Suzhou Ninth Hospital Affiliated to Soochow University, Suzhou, China, and colleagues.
The researchers reported no conflicts of interest. The study was supported by the 2024 Academy-level Research Initiation Fund Approval Contract of Suzhou Ninth People’s Hospital.
Source: Medicine
