A 29-year-old, G2 P1010, six-week pregnant female complained of abdominal pain for several hours. Past medical history was unremarkable except for a first trimester, spontaneous miscarriage. Physical exam was remarkable for left lower quadrant tenderness without peritoneal signs. Pelvic examination was normal and demonstrated a gravid uterus, consistent with dates. Laboratory studies were within normal limits, including a beta-HCG of 55,000.
A pelvic sonogram was done (image). The patient was subsequently taken to the operating room.
Diagnosis: Heterotopic Pregnancy
This sonogram shows the simultaneous development of a six-week intrauterine gestation (IUG) and an extrauterine gestation (EUG) in the left adnexa. The left adnexal mass is typical for an ectopic pregnancy, having a thickened echogenic ring, representing trophoblastic tissue or chorionic villi.
Before the age of assisted reproductive technology (ART), heterotopic pregnancies were rare, involving 1 in 30,000 pregnancies (note that our patient did not use ART). With more invasive means of fertilization, heterotopic pregnancies may be as common as 1.5 in 1000 ART pregnancies. The diagnosis is often delayed since the presence of an IUG may be misleading. Furthermore, the beta-HCG will be normal due to the presence of an IUG. The mortality rate for the IUG is estimated at 1 in 3. Standard treatment is surgical removal of the ectopic by salpingectomy or salpingostomy.
Our patient’s IUG was deemed nonviable. Cervical dilatation and suction was performed. The patient subsequently underwent laparoscopy to excise the right adnexal mass. Pathology confirmed the diagnosis.
Hagan-Ansert, S. First trimester complications. Ectopic pregnancy. In; Textbook of Diagnostic Ultrasonography 6th Ed. St. louis, Mo.: Mosby Elsevier; 2006, p. 1004-1009
Molinaro, T., and Barnhart, K., Abdominal pregnancy, cesarean scar pregnancy and heterotopic pregnancy. In UpToDate, version 15.2, 2007