Abstract
BACKGROUND: Ectopic pregnancy remains one of the most common causes of pregnancy-related deaths in the first trimester. About 2.4% of ectopic pregnancies occur in the interstitial part of the fallopian tubes. Given the nonspecific symptoms and the increased risk of hemorrhage associated with interstitial pregnancy localization, early diagnosis is crucial and should be based not only on clinical presentation but also on adjunctive diagnostic modalities. Early diagnosis leads to better treatment-related outcomes. Tubal ectopic pregnancies rarely progress into the second trimester and are typically diagnosed during the first trimester. CASE PRESENTATION: A 25-year-old primigravida at 20 weeks of gestation was initially diagnosed with a single live intrauterine pregnancy but presented with hypovolemic shock and was intraoperatively found to have an unruptured ectopic pregnancy. Postoperatively, the patient remained hemodynamically stable and was discharged on the fifth day. To date, the highest gestational age reported for a tubal ectopic pregnancy is 14 weeks. CONCLUSION: Ectopic pregnancies should be diagnosed in the first trimester via expert ultrasound. In this case, delayed second-trimester ultrasound in a low-income patient led to missed diagnosis. Clinical judgment must guide antenatal care, and surgery should not be delayed despite an unidentified source of hemoperitoneum.