Letters to the Editor

Considerations for Identifying Ectopic Pregnancy


Am Fam Physician. 2014 Dec 1;90(11):752a-753.

Original Article: Diagnosis and Management of Ectopic Pregnancy

Issue Date: July 1, 2014

Available at: https://www.aafp.org/afp/2014/0701/p34.html

to the editor: The authors mention that visualizing intrauterine gestational structures effectively rules out an ectopic pregnancy given the rarity of heterotopic pregnancy. However, it has been estimated that up to 1% of pregnancies conceived with assisted reproductive technologies are heterotopic,1 and with patients increasingly using such technologies, family physicians should maintain a high index of suspicion.

Also, one modality not discussed in the article is dilation and curettage, which can be performed in cases of assured nonviable pregnancy of unknown location. If there is an absence of chorionic villi in the pathologic specimen, then one can reasonably diagnose an ectopic pregnancy in the presence of other indicators, such as decreasing or inappropriately increasing quantitative human chorionic gonadotropin levels, even in the absence of diagnostic ultrasonographic findings. This approach can often save a woman from undergoing an invasive exploratory laparoscopic procedure.

Author disclosure: No relevant financial affiliations.


1. Svare J, Norup P, Grove Thomsen S, et al. Heterotopic pregnancies after in-vitro fertilization and embryo transfer—a Danish survey. Hum Reprod. 1993;8(1):116–118.

in reply: Assisted reproductive technologies increase the risk of hetero-topic pregnancy, although likely less than the 1% rate observed in a 1993 Danish survey.1 A more recent analysis of all registered assisted reproductive technology pregnancies in the United States from 1999 to 2002 reported an incidence of heterotopic pregnancy of 1.5 per 1,000 assisted reproductive technology pregnancies, or 0.15%.2 Nevertheless, we agree that clinicians must be aware of this possibility when treating a patient with a pregnancy of unknown location.

Although dilation and curettage has been advocated by some experts as a tool to assist in the diagnosis of a pregnancy of unknown location, this procedure risks disrupting a viable pregnancy. Furthermore, the absence of chorionic villi does not confirm an ectopic pregnancy because false-negative results are common; chorionic villi are not detected by histopathology in up to 20% of curettage specimens from elective termination of pregnancy.3

Finally, with the advent of methotrexate as a treatment option for suspected ectopic pregnancy, women can now routinely avoid the possibility of undergoing an invasive exploratory laparoscopic procedure, or even a less invasive curettage.

Author disclosure: No relevant financial affiliations.


1. Svare J, Norup P, Grove Thomsen S, et al. Heterotopic pregnancies after in-vitro fertilization and embryo transfer—a Danish survey. Hum Reprod. 1993;8(1):116–118.

2. Clayton HB, Schieve LA, Peterson HB, Jamieson DJ, Reynolds MA, Wright VC. A comparison of heterotopic and intrauterine-only pregnancy outcomes after assisted reproductive technologies in the United States from 1999 to 2002. Fertil Steril. 2007;87(2):303–309.

3. Lindahl B, Ahlgren M. Identification of chorion villi in abortion specimens. Obstet Gynecol. 1986;67(1):79–81.

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This series is coordinated by Kenny Lin, MD, MPH, Associate Deputy Editor for AFP Online.



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