By Frank W. Ling, MD
For the past decade, the management of ectopic pregnancy has evolved away from the old adage "Never let the sun set on a suspected ectopic pregnancy," to a less surgically-oriented approach. With the wider availability of high-resolution transvaginal ultrasound, the greater use of more specific and sensitive radioimmunoassays for human chorionic gonadotropin and progesterone, and a higher level of clinical suspicion on the part of practitioners, earlier diagnosis of ectopic gestation is possible, thereby increasing the potential for nonsurgical management. Even though surgical management has made great strides in minimizing morbidity and mortality in these cases, even fallopian tube-sparing procedures are potentially of greater risk to the patient than nonsurgical intervention. By no means have all the questions been answered, but the role of various diagnostic modalities have been greatly clarified.
The primary laboratory tool used in the evaluation and management of presumed ectopic pregnancies is the serum human chorionic gonadotropin level (hCG). Not only does it serve to identify the presence of a recent or ongoing pregnancy, but also it can be correlated with ultrasound findings to detect a normally developing intrauterine pregnancy. At an hCG level of 2000 mIU/mL, it is generally expected that ultrasound will visualize the intact gestation. Above this hCG level (discriminatory zone), if transvaginal sonography fails to identify the intrauterine pregnancy, a nonviable pregnancy is diagnosed. In the same way, if serial hCG levels do not rise or fall appropriately, the diagnosis of nonviable gestation is made. With the knowledge that a small percentage of ongoing normal pregnancies do not demonstrate the expected 66% rise over 2 days, the diagnosis of a failed pregnancy is generally reserved for those cases in which the rise does not reach 50% over that time, thereby eliminating the risk of intervening in an otherwise normal pregnancy. Under no circumstances, however, can hCG levels be used to identify the location of the nonviable pregnancy.
Not nearly as useful, this test is used by some to develop an index of suspicion of ectopic pregnancy. Generally a serum progesterone exceeding 25 ng/mL is found in an ongoing intrauterine pregnancy. Extremely low values, ie, less than 5 ng/mL, are associated with failed pregnancy. Intermediate levels are not as helpful. As with the serum hCG, the location of the failed pregnancy is not identified.
The discriminatory zone of 2000 mIU/mL mentioned above is greatly dependent upon local factors such as the skill level of the sonographer and the equipment used. The gestational age of approximately 5.5 weeks is associated with this hCG level. Although it has its own limitations including false-positive and false-negative findings, ultrasound does have the ability to identify the location of the gestation, both intra- and extra-uterine.
It has been widely suggested that uterine curettage/endometrial sampling/dilation and curettage should be performed to identify the presence or absence of chorionic villi to distinguish between a failed intrauterine pregnancy and ectopic gestation. The absence of villi would suggest either an ectopic pregnancy or a presumed completed abortion. In the former case, further therapy is likely, whereas in the latter case, no further treatment is warranted. If a completed abortion is suspected, then serial hCG levels should document an appropriate resolution.
The Answer to the Question is . . .
As with so much of clinical medicine, the answer is both "yes" and "no." Laparoscopy can play a role in both diagnosis and management of ectopic pregnancy, even in this age of increasing use of nonsurgical algorithms for diagnosis and methotrexate for treatment. In those cases in which the laboratory values and/or sensitive ultrasound are not available, the "gold standard" for the diagnosis of ectopic pregnancy is still surgical, in most cases via laparoscopy. Even when a firm diagnosis is made without the need for laparoscopy, nonsurgical management of ectopic gestation should only be embarked upon in a setting in which the patient can be relied upon to be compliant and accessible to the health care team. Otherwise, nonsurgical management would be fraught with excessive risk.
So what’s the point of this intellectual exercise? If laparoscopy is still needed for both diagnosis and treatment, why not simplify the entire management of these patients and revert to surgery for all? Some would still subscribe to this and, for their practice situation, perhaps correctly so. For the most part, clinicians and their patients can benefit from having a range of treatments for a particular condition. Ectopic pregnancy is no different. In some locations, laparoscopy is definitely still needed for diagnosis and/or treatment. In other practices, laparoscopy has been relegated to a role as "exception" rather than "rule."
Despite the ever-increasing use of nonsurgical diagnosis and treatment, laparoscopy should not be viewed as less than standard of care. In any given practice, the role of this surgical intervention may continue to evolve. Accumulation of more clinical data may well support even broader application of nonsurgical diagnostic and treatment modalities, but, for the foreseeable future, the clinician need not apologize for the use of a procedure that has, for decades, served patients very well.
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