Mock embryo transfer does not affect uterine contractility

ObjectiveTo assess the degree of utero-stimulation induced by transcervical introduction of a catheter as in mock ET.DesignProspective study.SettingReproductive medicine unit.Patient(s)Eighty volunteers undergoing mild ovarian stimulation and IUI.Intervention(s)Just before IUI, women had uterine contraction (UC) frequency assessed with 2-minute sagittal ultrasound scans of the uterus (precatheter measurement). Thereafter, one of three types of catheters, each with a different stiffness level (low, n = 25; medium, n = 30; or high, n = 25) was introduced into the cervix up to the inner cervical os, then immediately withdrawn, and the UC frequency reassessed (postcatheter measurement).Main Outcome Measure(s)Percentage change in UC frequency.Result(s)Median (range) UC frequency was not significantly different at pre- and postcatheter measurements: 2.0 (0.0–4.5) UC per minute and 2.2 (0.0–5.5) UC per minute. In addition, the stiffness of the catheter (low, medium, or high) did not influence the UC frequency, with median (range) percentage of change from pre- to postcatheter measurement at 0 (−100% to +75%), 0 (−100% to +100%), and 0 (−40% to +100%), respectively.Conclusion(s)The introduction of a catheter up to the inner cervical os, as usually performed in mock ET, does not stimulate uterine contraction frequency, irrespective of catheter stiffness.