Transvaginal versus transabdominal ultrasound guidance for embryo transfer in donor oocyte recipients: a randomized clinical trial.

Objective: To compare pregnancy and implantation rates with transvaginal (TV) versus transabdominal (TA) ultrasound-guided embryo transfer (ET).

Design: Randomized, clinical trial registered at clinicaltrials.gov (NCT 01137461).

Setting: Private, infertility clinic.

Patient(s): Three-hundred thirty randomized recipients of donor oocytes.

Intervention(s): Embryo transfer using TV (with empty bladder, using the Kitazato ET Long catheter) versus TA ultrasound guidance (with full bladder, using the echogenic Sure View Wallace catheter).

Main Outcome Measure(s): Overall pregnancy, clinical pregnancy, implantation, and ongoing pregnancy rates. Duration and difficulty of ET. Patient-reported uterine cramping and discomfort, as evaluated by questionnaire.

Result(s): No statistically significant differences were observed in clinical pregnancy 50.9% versus 49.4% (95% confidence interval of the difference: -9.2 to +12.2%), implantation 34.5% versus 31.4% (95% CI of the difference: -4 to +10.3%) between the TV and TA ultrasound-guided groups. Transfer difficulty (6% versus 4.2%) and uterine cramping (27.2% versus 18.3%) were not statistically significantly different between treatment groups. Total duration (154±119 versus 85±76 seconds) was statistically significantly higher in the TV ultrasound group. Light to moderate-severe discomfort related to bladder distension was reported by 63% of the patients in the TA ultrasound group.

Conclusion(s): Transvaginal ultrasound-guided ET yielded similar success rates compared with the TA ultrasound-guided procedure without requiring the assistance of a sonographer. It was associated with increased patient comfort due to the absence of bladder distension.