Conversely, if symptoms of pregnancy persist or worsen after laparotomy for ectopic pregnancy, the surgeon should suspect another pregnancy.7 Even when a patient who is being treated for infertility exhibits signs and symptoms of ectopic pregnancy, concurrent intrauterine pregnancy must be ruled out.9
A persistent Hegar’s sign or Chadwick’s sign means that a pregnancy is still present.7 In addition, the absence of vaginal bleeding after surgery for ectopic pregnancy may indicate the presence of gestation.6
Few heterotopic pregnancies are identified before surgery
Only 10% of heterotopic pregnancies are detected preoperatively.3 One third of intrauterine gestations in a heterotopic pregnancy spontaneously abort.11
Don’t assume that the presence of an intrauterine gestation excludes the possibility of ectopic pregnancy when the patient experiences abdominal pain.16
Imaging is helpful but not foolproof
Identifying a heterotopic pregnancy before surgery is an imaging challenge. Even when US is employed, the diagnosis is missed in 50% of cases—and even transvaginal US has low sensitivity.17,18 One reason may be the discordant appearance of fetal cardiac activity in coexisting intrauterine and ectopic pregnancies. Alternatively, the gestational sac may be anembryonic.19
A gestational sac is a sonolucent structure with a double decidual sac sign—i.e., an echogenic ring surrounding the sac. A pseudogestational sac containing fluid or blood can mimic a gestational sac.5 One helpful diagnostic sign of heterotopic pregnancy during US examination is a lateral location of one of the gestational sacs.16
If two corpora lutea are present on US—or even at laparotomy or laparoscopy—suspect heterotopic pregnancy.7
Obstetric imaging should include views of the adnexae
The adnexa and surrounding structures are usually not imaged during obstetric US because the focus is on the intrauterine gestation.5 In addition, ultrasonographers are frequently misled by the presence of fluid in the uterus.
It is important for the ultrasonographer to examine the entire pelvic region for pregnancy (FIGURE), especially in women who have been treated with ART or who have pelvic inflammatory disease or a history of pelvic surgery.11 The adnexae should be assessed during every obstetric US, especially in women who are at risk of ectopic pregnancy.5
FIGURE When a pregnancy wanders, there are many possibilities for where
Ectopic pregnancy can arise as a result of internal migration of a fertilized ovum or transperitoneal migration of sperm. It may be observed at a number of possible sites within the pelvis.
Serial beta-hCG levels aren’t helpful
In heterotopic pregnancy, both gestations produce hCG, so the assessment of serial serum quantitative beta-hCG levels is not informative.11
When treating ectopic pregnancy, hold off on curettage
Ectopic pregnancy and extrauterine gestation are life-threatening emergencies that require timely diagnosis and treatment.5,19 The traditional treatment for ectopic pregnancy is laparotomy or laparoscopy with removal of the ectopic pregnancy, followed by dilation and curettage (D&C). The curettage removes the decidual cast and clots and is intended to prevent postoperative bleeding. However, curettage could destroy any intrauterine pregnancy that is not yet diagnosed. Therefore, D&C should be withheld until the uterus is confirmed to be empty.10