Ectopic Pregnancy: A Clinical Casebook

17. Heterotopic Pregnancy

Mallory Stuparich1 and Kimberly A. Kho 

(1)

Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., 75390-9032 Dallas, TX, USA

Kimberly A. Kho

Email: kimberly.kho@gmail.com

Keywords

Heterotopic pregnancyKCl injectionHyperosmolar glucose injection

Case Presentation

A 31-year-old female was transferred to the emergency department from an outside facility with an established intrauterine pregnancy and abdominal pain. Her estimated gestational age was 10 weeks by the last menstrual period and her medical history was significant for a prior laparoscopic right salpingectomy for an ectopic pregnancy as well as being a current tobacco smoker. She was initially hypotensive at the outside facility, so she had been given two units of packed red blood cells and resuscitated with 4 L of crystalloid prior to her arrival in the emergency department. The patient denied having any vaginal bleeding. Physical examination revealed an uncomfortable patient with abdominal rebound and tenderness. Bimanual examination was significant for a 10-week uterus and cervical motion tenderness. The serum β-hCG level was 58,383 mIU/L. Transvaginal ultrasound revealed an intrauterine pregnancy with cardiac motion as well as a right adnexal mass and free fluid in the posterior cul-de-sac and extending into Morrison’s pouch. With this clinical picture, the decision was made to take the patient to the operating room for diagnostic laparoscopy.

My Management

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Diagnosis and Assessment

Since the patient had signs of hemodynamic instability and an acute abdomen on physical examination with signs of hemoperitoneum, the patient was taken emergently to the operating room for diagnostic laparoscopy . The differential diagnosis at that time included a ruptured ectopic pregnancy , a ruptured ovarian cyst with ongoing bleeding, rupture of the ectopic portion of a heterotopic pregnancy , bleeding from another intra-abdominal source, or visceral perforation. Each of these situations requires surgical intervention.

A heterotopic pregnancy describes simultaneous pregnancies at two different implantation sites. Most commonly, one pregnancy is implanted in the uterus and at least one other is implanted outside the uterus in an ectopic pregnancy [1]. The ectopic component of a heterotopic pregnancy can be located within the abdomen, ovary, and cervix, but it is most commonly located within the fallopian tube [1]. The spontaneous incidence of a heterotopic pregnancy with natural conception is estimated to be 1 in 30,000 pregnancies with the incidence rising to approximately 1 in 100 pregnancies with the use of assisted reproductive technologies (ART), including in vitro fertilization, embryo transfer, and use of ovarian stimulating drugs [14]. In vitro fertilization remains the most important risk factor for heterotopic pregnancy [5]. The risk for heterotopic pregnancy is increased by any cause of tubal damage, which can include but is not limited to a history of pelvic inflammatory disease (PID), prior tubal surgery, endometriosis, or cigarette smoking [156].

Identifying a heterotopic pregnancy requires a high index of suspicion and may be a challenging diagnosis to make due to the tendency for clinicians to eliminate the possibility in the absence of maternal risk factors and upon diagnosis of an intrauterine pregnancy even in the setting of signs and symptoms of a simultaneous ectopic pregnancy. A heterotopic pregnancy has the potential for significant maternal morbidity, including blood transfusion, and it can have catastrophic outcomes if the diagnosis is delayed, including hemorrhagic shock and fetal loss. Thus, the possibility of a heterotopic pregnancy should not be eliminated once an intrauterine pregnancy is diagnosed.

The patient in the case was at increased risk for a recurrent ectopic pregnancy given her history of prior salpingectomy for an ectopic pregnancy (odds ratio 12.5 for recurrence) and her cigarette use (odds ratio 3.9 for > 20 cigarettes daily) [7]. Typically, vaginal bleeding is absent in heterotopic pregnancies as seen with this patient [5]. Signs and symptoms suspicious for a heterotopic pregnancy include abdominal pain, presence of an adnexal mass, peritoneal irritation, and an enlarged uterus [8]. The patient’s physical examination was concerning for an acute abdominal process, and while ultrasound did demonstrate an intrauterine pregnancy, it also demonstrated a large amount of fluid extending into Morrison’s pouch, concerning for intraperitoneal bleeding. Ultrasound is notoriously unreliable for the detection of heterotopic pregnancy, and in one review of the literature, only 66 % of cases reviewed were diagnosed sonographically [4]. This underscores the importance of a methodical, thorough clinical, and sonographic examination of the maternal adnexae even if an intrauterine pregnancy is detected and especially if there is free fluid identified within the pelvis or the patient’s clinical picture is concerning for an acute abdominal process [3]. In addition, repeated systematic ultrasound examinations increase the potential for detection of a heterotopic pregnancy [5].

Management

Unique to heterotopic pregnancy, one must consider the effect of treatment on the intrauterine pregnancy, which can be preserved in many cases and generally has a favorable prognosis with an estimated 50–70 % survival rate [14]. Heterotopic pregnancies frequently present with hemodynamic instability, and treatment must be initiated rapidly to prevent maternal and fetal harm. In a hemodynamically unstable patient, the concurrent diagnosis and treatment of a heterotopic pregnancy is achieved with surgical intervention either by laparoscopy or laparotomy [3]. Laparoscopy may be the preferred operative approach, but depends on the availability of necessary surgical equipment as well as technical skill of the surgeon. Laparotomy may be chosen in cases with large amounts of intra-abdominal bleeding or hemorrhagic shock . Surgery should be performed as early as possible to prevent an emergent, catastrophic scenario and to improve the survival of the intrauterine pregnancy. In a clinically stable patient, diagnostic laparoscopy can be performed in order to make an accurate diagnosis when clinical presentation and imaging are unclear. Laparoscopy with evacuation of hemoperitoneum, identification of a dilated, ruptured fallopian tube, and left salpingectomy were performed in this patient. Intraoperatively, a 10-week fetus and placenta were identified extruding from the fallopian tube into the abdomen, and this finding was confirmed on pathologic assessment.

If the patient is hemodynamically stable, one may consider medical treatment with injection of either potassium chloride or hyperosmolar glucose into an intact heterotopic gestational sac or fetus during laparoscopy or using ultrasound guidance. This approach is being used with increasing frequency [9]. In a small series of ectopic abdominal pregnancies receiving potassium chloride injection into the gestational sac, 75 % of the concurrent intrauterine pregnancies resulted in delivery of a viable neonate at 36 weeks or greater [9]. Systemic medical treatment with methotrexate is contraindicated due to potential catastrophic effects on the viable intrauterine pregnancy.

Lastly, the ectopic portion of some heterotopic pregnancies can resolve spontaneously without initiating any intervention. There have even been case reports in which abdominal ectopic pregnancies have resulted in the birth of a viable neonate in addition to the intrauterine neonate [9]. There are currently no clear guidelines or diagnostic tests that demonstrate which women are appropriate candidates for observation. Serial assessment of serum β-hCG is not helpful, and it remains unclear whether or not serial sonographic assessment is helpful when following up these patients [5].

Outcome

The patient did well postoperatively and remained hemodynamically stable. Ultrasound was performed postoperatively, which confirmed the presence of a viable intrauterine pregnancy. The patient was discharged on the second postoperative day. The remainder of her antepartum course was uncomplicated and she went on to have an uneventful vaginal delivery at term.

Clinical Pearls/Pitfalls

·               Detection of an intrauterine pregnancy does not rule out the possibility of a simultaneous ectopic pregnancy.

·               Serial serum beta hCG measurement is not a reliable method of detecting and following up a heterotopic pregnancy.

·               Systemic methotrexate should not be used to treat the ectopic portion of a heterotopic pregnancy due to the risks to the intrauterine pregnancy

·               When a patient is diagnosed with a heterotopic pregnancy, prompt management is preferred to prevent the need for emergent treatment of a ruptured ectopic pregnancy.

·               Management of an unruptured ectopic pregnancy may be accomplished by medical management (KCl or hyperosmolar glucose, but not methotrexate) with good outcomes for the intrauterine pregnancy (Figs 17.1 and 17.2).

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Fig. 17.1

Adnexal mass and ovary surrounded by fluid and clot. (Courtesy of Elysia Moschos, MD)

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Fig. 17.2

Uterus with intrauterine gestational sac surrounded by free fluid. (Courtesy of Elysia Moschos, MD)

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