Pregnancies of unknown location after in vitro fertilization minimally invasive management with Karman cannula aspiration

Outpatient management of pregnancies of unknown location using endometrial sampling with a Karman cannula aspiration can obviate the need for methotrexate.

Paula Brady, M.D., Anthony N. Imudia, M.D., Awoniyi Awonuga, M.D., Diane L. Wright, Ph.D., Aaron K. Styer, M.D., Thomas L. Toth, M.D.

Volume 101, Issue 2, Pages 420-426, February 2014


To describe a standardized protocol for the assessment of asymptomatic patients with pregnancies of unknown location (PUL) after IVF.

Retrospective cohort study.

University-based infertility clinic.

Women undergoing fresh IVF/intracytoplasmic sperm injection (ICSI) cycles between 2005 and 2011.

Endometrial sampling using Karman suction cannula in patients with PUL and abnormal β-hCG trend (increase <53% or decrease <15% in 2 days) and a pelvic ultrasound unremarkable for an intrauterine pregnancy (IUP) or an ectopic pregnancy (EP). Main Outcome Measure(s):
Proportion of patients spared methotrexate (MTX) administration.

Endometrial sampling was performed in 45 patients. Of these, 31 (68.9%) were diagnosed with failed IUP by either a sampling after the β-hCG decline (≥15%) and/or the presence of villi on final pathology. No further intervention was required. Fourteen patients (31.1%) were diagnosed with presumed EP by persistent β-hCG level after negative pathology. Ten of these patients (71%) were successfully treated with a single dose of MTX; three required an additional dose, and one required laparoscopy for a ruptured EP.

In asymptomatic patients with PUL and abnormal β-hCG trends after IVF, the utility of Karman aspiration to confirm an IUP may obviate treatment with MTX in more than two-thirds of patients.

  • Amanda N. Kallen

    Thank you for addressing this very common clinical dilemma in our practice! While you mention as one limitation of the study the fact that practitioners had different practice patterns with respect to cannula size and number of hcg levels obtained, I feel that this actually increases the generalizability of your study. It’s interesting that the presence of villi was of no utility in the final diagnosis. Based on your results, would you advocate for making the final diagnosis of failed IUP based solely on serology after aspiration?

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