Save of the Month: Heterotopic Pregnancy

SAVE OF THE MONTH – Thank you Dr. Amy Sanghvi for an unbelievable save of a mother with…. drumroll….. a heterotopic pregnancy!!!

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Thanks to Dr. Wendy Chan for the nomination.

Here’s the scene:

A 30 year-old woman G₂P₁ presented at 8 weeks EGA with worsening abdominal cramps on the right side and vaginal spotting. She had no fever/chills but did report dysuria. She had HR 100 and BP 125/76. Dr. Sanghvi noted her to have significant lower abdominal tenderness. The initial bedside ultrasound showed a +IUP, a left sided ovarian cyst, and small free fluid around her right ovary. They sent the patient for an official sonogram to rule out torsion. The radiologist interpretation was: Single live IUP at 8w6d. Complex 3cm cyst on the left; cannot see right ovary. Free fluid was noted. Radiology’s “differential” included ovarian torsion versus “other mass.”

Obstetrics/gynecology thought that the patient may have appendicitis and recommended involving surgery. Dr. Sanghvi relied on her bedside sonogram and the formal study and admitted the patient to the Ob/gyn service for a diagnostic laparoscopy. The general surgeons and obstetricians debated, but ultimately the patient did go to the OR for a diagnostic laparoscopy. There was gross hemoperitoneum with dark clot and 350cc of blood and an ectopic pregnancy in the right fallopian tube, which was ruptured and bleeding. The patient underwent an uncomplicated right salpingectomy and was discharged from the hospital the next day with her IUP viable, all thanks to Dr. Sanghvi’s great save!

Heterotopic pregnancies (HP) occur in 1/30,000 traditional pregnancies. With reproductive assistance, it is much more common and may occur in up to 5% of patients following in vitro fertilization (2). While they can be found at any time during pregnancy, 90% are found in the first trimester (mostly 5-8 weeks gestation like this patient) (1).

heterotopic 1

One retrospective series found the sensitivity of transvaginal ultrasound for diagnosing a heterotopic pregnancy to be 56% at 5-6 weeks gestation (3). However, a more recent retrospective review of 174 cases of HP found the sensitivity to be 92% (specificity 100%) with transvaginal ultrasound at 3-5 weeks (4). Despite the higher sensitivity, 10 cases were missed, and all required surgery for a ruptured ectopic. Four patients had miscarriages of their co-existent IUP after surgery – there were significantly more miscarriages in patients who were missed than patients who were correctly diagnosed with HP by ultrasound (70% v. 26%) (4). Missing the diagnosis of HP is common due to false reassurance after identifying an intrauterine pregnancy (4). Patients will also have normal beta-HCG levels due to the presence of the co-ex heterotopic 2 isting IUP (5). This missed or delayed diagnosis leads to increased incidence of ectopic rupture, hypovolemic shock, blood transfusions, as well as death of the desired IUP (4). Therefore, although ultrasound is important and can be very helpful in quickly establishing the diagnosis of an IUP, relying too much on this test for ruling out an ectopic pregnancy can be devastating. If suspicion is high, the patient should considered for diagnostic and therapeutic laparoscopy.
In the case of rupture, the treatment is always surgical (1). If unruptured, treatment options include expectant management with embryo aspiration or local injection of feticides (KCl or hyperosmolar glucose); methotrexate is contraindicated in heterotopic pregnancies (5).

Take home points:

Keep heterotopic pregnancies on your differential!!
Don’t stop your ultrasound after you find the IUP -> Look in the adnexa! You may find a cystic mass or free fluid.
If you see free fluid in the pelvis, take 1 minute to complete the FAST so as to not miss significant hemoperitoneum; this may suggest a ruptured heterotopic pregnancy
Bedside ultrasound is not perfect; if your suspicion is high, consider obtaining a formal study and encourage your consultants to take that patient to the OR for definitive diagnosis.

References:

Hassani et al. Heterotopic pregnancy: A diagnosis we should suspect more often. J Emerg Trauma Shock. 2010 Jul-sep;3(3):304.
Cohen J, et al. In vitro fertilization and embryo transfer, a collaborative study of 1163 pregnancies to the incidence and risk factors of ectopics pregnancies. Hum Reprod. 1986;4:255–8.
Fleischer AC, et al. Ectopic pregnancy: features at transvaginal sonography. Radiology. 1990;174:375–8.
Li XH, Ouyang Y, Lu GX. Value of transvaginal sonography in diagnosing heterotopic pregnancy after in-vitro fertilization with embryo transfer. Ultrasound Obstet Gynecol. 2013;41:563–9
Refaat, B, et al. Ectopic pregnancy secondary to in vitro fertilisation-embryo transfer: pathogenic mechanisms and management strategies. Reprod Biol Endocrinol.2015 Apr 12;13:30. doi: 10.1186/s12958-015-0025-0.

Edited by: Dr. Ian deSouza