LAUSR

We read with great interest the article by Fridman et al entitled “Methotrexate Administration to Patients with Presumed Ectopic Pregnancy Leads to Methotrexate Exposure of Intrauterine Pregnancies.” This is a rarely reported but important issue faced by the medical fraternity and patients. They concluded that most patients who had received methotrexate in the cohort were lacking definitive sonographic features and a delay in methotrexate treatment may be beneficial. We echo the views of Fridman et al. We recently encountered a 32-year-old woman with amenorrhea for 6 weeks and a positive urine pregnancy test. Transvaginal sonography showed the absence of an intrauterine gestational sac. However, a 3 × 2-cm right adnexal mass was noted (Figure 1). The patient was asymptomatic and hemodynamically stable. A provisional diagnosis of ectopic pregnancy was made, and she was keen for methotrexate treatment. Her serum β-human chorionic gonadotropin (hCG) was 584 IU/L, she had no contraindication to methotrexate, and she was willing to comply with close follow-up. According to guidelines from the Royal College of Obstetricians and Gynaecologists, the National Institute for Health and Care Excellence, and the algorithm from uptodate.com, this patient fulfilled all the criteria for methotrexate treatment, including the range of β-hCG, which was between 200 and 5000 IU/L. However, in view of the serum β-hCG being below the discriminatory zone, the obstetrician decided to repeat a β-hCG after 48 hours, which showed a reading of 1674 IU/L, a substantial increase that suggested a high probability of intrauterine pregnancy. The diagnosis was revised to possible intrauterine pregnancy, and methotrexate was withheld. One week later, a repeat scan showed a viable intrauterine gestational sac (Figure 2). Retrospectively, the misdiagnosis was due to an early scan and the misleading cyst. A discriminatory level of serum β-hCG has been accepted at 1500 to 2000 IU/L. Below this level (which had also happened in a substantial proportion of the population reported by Fridman et al), there is a high possibility