Table 3. ET difficulty parameters for semi-rigid and flexible catheters
  Group 1
Semi-rigid catheter
Group 2
Flexible catheter
Blood after ET 36/363 (9.9%) a 13/340 (3.8%) b
Use of a tenaculum and/or hysterometer 72/363 (19.8%) a 20/340 (5.9%) b
Ultrasound guidance 32/363 (12.1%) a 16/340 (5%) b
Retained embryos 12/363 (3.3%) a 23/340 (6.8%) b
a,b Values with different letters inside the line differed significantly (P<0.05).