Enhancing Detection and Management of Spontaneous Bilateral Ectopic Pregnancies: Insights From a Rare Case

Introduction

Ectopic pregnancy (EP), defined as implantation of a fertilized ovum outside the uterine cavity, affects approximately 1–2% of all pregnancies and remains a leading cause of first-trimester maternal morbidity and mortality, with an estimated mortality rate of 0.2 per 1000 cases [1]. The vast majority of EPs – up to 97% – occur within the fallopian tubes [2]. Bilateral tubal ectopic pregnancy (BTP), in which simultaneous implantation occurs in both fallopian tubes, is an exceptionally rare clinical entity. The first case was described by De Ott in 1891 [3], and since then, only sporadic cases have been reported. The estimated incidence of BTP ranges from 1 in 725 to 1 in 1580 ectopic pregnancies, although the true incidence is likely under-recognized due to diagnostic limitations [4].

BTP has been most commonly associated with assisted reproductive technologies (ART), prior tubal surgery, pelvic inflammatory disease (PID), and the use of intrauterine contraceptive devices [5]. However, spontaneous BTP occurring in the absence of fertility treatment is even rarer. These cases present significant diagnostic challenges, particularly because conventional diagnostic tools are not reliably sensitive to bilateral disease. Transvaginal ultrasonography remains the cornerstone of EP diagnosis, with reported sensitivities ranging from 87% to 99% for unilateral tubal pregnancies [6]. However, simultaneous detection of ectopic gestations in both tubes is infrequent and often missed due to overlapping adnexal structures, hematosalpinx, or limited field of view [7]. Moreover, the presence of a pseudo-sac in the uterine cavity can create false reassurance of an intrauterine pregnancy, further complicating diagnosis in suspected ectopic or heterotopic cases [8]. In many instances, BTP is diagnosed intraoperatively, often incidentally, emphasizing the necessity for systematic inspection of both fallopian tubes during surgical management of suspected EP [9].

Confirmation of BTP requires histopathologic evidence of chorionic villi within both fallopian tubes [10]. The consequences of missed or delayed diagnosis are substantial, including tubal rupture, intra-abdominal hemorrhage, and compromised fertility potential. Management is typically surgical, with bilateral salpingectomy often performed when tubal rupture or extensive damage is present. Alternatively, conservative approaches such as bilateral salpingostomy may be considered in select cases where fertility preservation is desired and tubal integrity is intact [11]. Systemic methotrexate, a common medical treatment for EP, is rarely suitable for BTP given diagnostic uncertainty and limited efficacy in cases involving bilateral disease [12]. Notably, no formal clinical guidelines currently exist to address the optimal diagnostic or management strategies for BTP, leaving decision-making to clinician judgment and institutional experience.

We report a rare case of spontaneous bilateral tubal ectopic pregnancy in a patient without known risk factors or prior fertility treatment. Despite adherence to standard diagnostic and operative protocols, the contralateral ectopic pregnancy was initially missed, highlighting the need for heightened clinical suspicion and thorough intraoperative evaluation. This case underscores both the diagnostic complexity and the clinical importance of considering bilateral ectopic implantation in patients presenting with persistent symptoms following initial treatment of a unilateral ectopic pregnancy.

Case Report

A woman in her late twenties, Gravida 3 Para 2 with 2 previous vaginal deliveries, presented to the Emergency Department with a 24-hour history of light vaginal bleeding and left lower-quadrant pain not responding to simple analgesia. Based on her last menstrual period, she was at 7 weeks of gestation and had conceived naturally without any assisted reproductive technique treatments. She denied any shoulder tip pain but reported lightheadedness. She had no significant medical history, was a non-smoker, and was not using any form of contraception at the time of conception.

On initial assessment, she generally appeared to be well. Vital signs demonstrated a blood pressure of 114/62 mmHg with mild tachycardia (heart rate 107 beats per minute). Abdominal assessment revealed mild left iliac fossa tenderness without palpable masses or abdominal distension. Speculum examination visualized a healthy, closed cervix without active bleeding.

Following a positive urine pregnancy test at triage, transvaginal ultrasonography was performed to evaluate pregnancy location. Ectopic pregnancy was the primary consideration in the differential diagnosis, as the patient had not had previous scans in this pregnancy. The ultrasound showed an anteverted uterus of normal size and shape with obvious free fluid behind the cervix. The endometrium was thickened to 17.3 mm, with an irregular fluid-filled area lacking the characteristic double-decidual sign suggestive of a gestational sac. The larger cystic region contained homogeneous debris measuring 21.9×20.45×9.97 mm with an overall volume of 2.33 ml. The right ovary appeared normal. Medial to the right ovary was a sac with a hyperechoic double rim suggestive of a gestational sac with a possible yolk sac, measuring 5.1×6.1×6.0 mm (MSD 5.7 mm, equivalent to 5 weeks of gestation). No definite fetal pole was observed. Free fluid was present in both adnexae. The left ovary contained a large simple cyst measuring 41.59×44.84×36.54 mm with an overall volume of 35.7 ml. There was 20.1 mm of free fluid in the pouch of Douglas. The radiologist’s impression was a likely leaking right-side ectopic pregnancy (Figure 1). The serum βhCG level was 4343 UI/L.

After comprehensive counseling regarding the diagnosis of right ruptured ectopic pregnancy, the patient provided informed consent for emergency laparoscopic salpingectomy and drainage of the left ovarian cyst. Medical management was not considered appropriate given the ultrasound findings suggesting rupture. With no prior history of fertility issues, laparoscopic salpingectomy rather than salpingostomy was recommended as the first-line approach [1].

Interestingly, intraoperative findings contradicted the imaging assessment – the ectopic pregnancy was identified in the left fallopian tube rather than the right as indicated by ultrasound. The surgical team proceeded with left salpingectomy and specimen preservation for histopathological examination, along with drainage of the left ovarian cyst (Figure 2). The estimated blood loss was 100–250 ml. The procedure was completed without complications, allowing same-day hospital discharge.

Following national guidelines, the patient was advised to perform a urine pregnancy test after 3 weeks and to seek medical attention if positive [1]. She was also counseled about her increased risk of recurrent ectopic pregnancy, warranting earlier scans in future pregnancies. As histopathology confirmed chorionic villi in the left fallopian tube specimen, establishing the diagnosis of ectopic pregnancy, no serial serum βhCG monitoring or follow-up ultrasounds were scheduled.

On day 17 after surgery, she returned to the gynecological Emergency Department with ongoing nausea and intense intermittent abdominal, vaginal, and rectal pain, accompanied by right-sided shoulder pain – a potential indicator of diaphragmatic irritation from intraperitoneal bleeding. Notably, she denied vaginal bleeding or discharge. Upon clinical assessment, vital signs were normal except for mild tachycardia (HR 108 beats/min). Urinalysis again yielded a positive pregnancy test. Abdominal examination revealed appropriate healing of laparoscopic port sites without infection. Suprapubic tenderness was noted on palpation, without signs of peritonism or acute surgical abdomen. Vaginal examination demonstrated a long, closed cervical os with positive cervical motion tenderness.

Despite these concerning symptoms, the provisional diagnosis was documented as postoperative infection/pain. Laboratory investigations, including hemoglobin concentration, renal function, and inflammatory markers, were within normal ranges. Following clinical protocol, she was discharged home with arrangements for the earliest available pelvic ultrasound to exclude postoperative complications.

The ultrasound, performed 48 hours after this second presentation, surprisingly revealed a live ectopic pregnancy in the right fallopian tube with free fluid in the pouch of Douglas and around the right adnexa (Figure 3). This confirmed a bilateral tubal ectopic pregnancy that had been missed during the initial surgery. Emergency surgical management was planned, and in an attempt to preserve fertility, salpingostomy was considered as the primary approach, with salpingectomy as a backup if necessary.

Intraoperatively, the right tube was found to be ruptured and unsalvageable, necessitating salpingectomy. The specimen was sent for histopathological analysis, which subsequently confirmed the presence of chorionic villi, establishing the diagnosis of a second tubal ectopic pregnancy. The procedure was completed without immediate complications.

The follow-up plan included urine pregnancy testing after 3 weeks, with instructions to contact the Emergency Department if positive. A face-to-face debrief appointment was scheduled to discuss this unusual case with the patient and address any concerns regarding her future fertility.

Discussion

LEARNING POINTS:

A thorough exploration of both fallopian tubes is crucial during the assessment of ectopic pregnancy, whether performed via ultrasound or laparoscopy, even when an ectopic pregnancy has already been conclusively identified in one tube. When there is any discrepancy between ultrasonographic findings and intraoperative discoveries, clinicians must maintain a heightened level of vigilance for the possibility of a bilateral ectopic pregnancy. In such situations, it is important to establish appropriate follow-up protocols after procedures like salpingectomy, even though current clinical guidelines may offer limited direction on managing these complex cases. Furthermore, in patients who present with persistent or recurrent abdominal pain following treatment for ectopic pregnancy, clinicians should keep bilateral or missed ectopic pregnancy high on the differential diagnosis, especially in the presence of a positive pregnancy test. Equally important is ensuring clear communication with patients about the rarity of their condition, coupled with comprehensive postoperative follow-up plans, as these are essential components of providing patient-centered care.

Conclusions

This case of spontaneous bilateral tubal ectopic pregnancy highlights several important clinical lessons. The extreme rarity of this condition contributes to diagnostic challenges that can impact patient outcomes. Our experience emphasizes the critical importance of thoroughly examining both fallopian tubes during ultrasound assessment and laparoscopy, even when pathology is identified on only 1 side. When discrepancies exist between imaging findings and intraoperative discoveries, clinicians should maintain heightened vigilance for the possibility of bilateral ectopic pregnancy. This case demonstrates the importance of raising awareness among clinicians about the possibility of BTP and highlights the need of established post-salpingectomy surveillance protocols in imaging-surgical discrepancies occur in cases of ectopic pregnancies.