Ultrasound measurement of the uterocervical angle before embryo transfer: a prospective controlled study

BACKGROUND: The study aim was to determine whether moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound could improve pregnancy and implantation rates. METHODS: Patients were alternately allocated to one of two groups. In the ultrasound-guided group (n = 320), the catheter was moulded according to the uterocervical angle measured by abdominal ultrasound. In controls (n = 320), embryo transfer was performed using the 'clinical feel' method. RESULTS: Moulding the embryo transfer catheter according to the uterocervical angle significantly increased clinical pregnancy [(OR = 1.57, 95% CI (1.08-2.27)] and implantation rates [(OR = 1.47, 95% CI (1.10-1.96)] compared with the 'clinical feel' method. It also significantly reduced difficult transfers [(OR = 0.25, 95% CI (0.16-0.40)] and blood during transfers [OR = 0.71, 95% CI (0.50-0.99)]. Patients with large angles (>60degrees) had significantly lower pregnancy rates compared with those with no angle [OR = 0.36, 95% CI (0.16-0.52)]. CONCLUSIONS: Moulding the embryo transfer catheter according to the uterocervical angle measured by ultrasound increases clinical pregnancy and implantation rates and diminishes the incidence of difficult and bloody transfers.