Diagnostic Challenges of Cervical Ectopic Pregnancy Presenting As Pregnancy of Unknown Location in the Emergency Department

Introduction: Cervical ectopic pregnancy is a rare form of ectopic implantation within the endocervical canal, accounting for approximately 1% of all ectopic cases. Presentation can be similar to early intrauterine pregnancy or a pregnancy of unknown location (PUL). In acute care settings, timely diagnosis and management are key to optimizing patients outcomes. Case: A 31-year-old G7P2042 female with a history of multiple dilation and curettage procedures presented with vaginal bleeding and pregnancy of unknown location (PUL), requiring obstetric evaluation in the emergency department. Prior visits to the ED demonstrated appropriately rising β-hCG. Ultrasound findings at that time showed a gestational sac without a fetal pole in the lower uterine segment, suggesting early uterine pregnancy versus threatened abortion or cervical implantation. On presentation, there was scant active bleeding. Pelvic exam revealed a fingertip-dilated cervix and a 3 cm dark red palpable mass on the external os. Transvaginal ultrasound confirmed a gestational sac with cardiac activity within the endocervical canal, consistent with a 7 + 1 week cervical ectopic pregnancy. Given hemodynamic stability and desire to preserve fertility, multidose systemic methotrexate therapy with folinic acid rescue was initiated. Despite continued β-hCG rise and intermittent bleeding, repeat TVUS confirmed loss of fetal cardiac activity, followed by appropriate decline of β-hCG levels. She later conceived a viable intrauterine pregnancy the following year. Discussion: This case highlights the diagnostic challenges of cervical ectopic pregnancy in the emergency setting, where initial findings may mimic early intrauterine pregnancy or pregnancy loss. Clinicians should maintain suspicion for ectopic implantation in patients with persistent early bleeding, particularly when ultrasound findings are inconclusive. Transvaginal ultrasound and physical exam are critical diagnostic tools, as β-hCG trends are not diagnostic of implantation location. Misdiagnosis can result in inappropriate uterine evacuation, which carries significant risks of hemorrhage in cervical implantation. This case underscores the importance of early multidisciplinary involvement in emergent obstetric settings. OB hospitalists are essential for timely diagnosis, initiation of medical management with methotrexate, and avoidance of surgical intervention and its complications.