To the Editor:
We welcome the recently published article by the Practice Committee of the American Society for Reproductive Medicine on the medical treatment of ectopic pregnancy (EP) (1). In selected patients, Methotrexate (MTX) is an effective treatment for unruptured EP and helps to avoid surgical intervention.
We are however concerned about some aspects of the committee’s opinion. The document advocates the use of single measurements of serum human chorionic gonadotropin (hCG) as a discriminatory zone to separate abnormal from normal gestations at the first presentation, if a transvaginal ultrasound scan (TVS) fails to identify the location of a pregnancy. This approach is not without risk. For example, it does not take into account the possibility of a multiple pregnancy where for a given gestational age serum hCG levels are higher than in a singleton. Consequently, hCG levels in multiple pregnancies are usually much higher before the pregnancy reaches a size that may be visualized on TVS (2). This could result in the administration of MTX to a woman with a pregnancy of unknown location (PUL) who has a developing twin pregnancy rather than an underlying EP. Such an outcome would in all likelihood lead to major congenital abnormalities in the developing fetuses. We recommend that the diagnosis of EP be based on the positive identification of an EP mass if inappropriate use of MTX is to be avoided. In the event of a PUL, waiting 48 hours to determine the hCG ratio has been shown to be a safe management approach, which offers further reassurance if the ratio is incompatible with a viable IUP (3). Read the rest of this entry »