Table 6. ET difficulty and efficiency parameters over time for the flexible catheter
  Quartiles
First (n=85) Second (n=85) Third (n=85) Fourth (n=85)
Transferred embryos 2.6 ± 0.9 2.8 ± 1.1 2.7 ± 1.1 2.7 ± 1.2
Blood after ET 4/85 (4.7%) 3/85 (3.5%) 3/85 (3.5%) 3/85 (3.5%)
Use of a tenaculum 8/85 (9.4%) a 7/85 (8.2%) ab 4/85 (4.7%) ab 1/85 (1.2%) b
Use of a hysterometer 2/85 (2.4%) 1/85 (1.2%) 0/85 (0%) 1/85 (1.2%)
US guidance required 4/85 (4.7%) 5/85 (5.9%) 4/85 (4.7%) 3/85 (3.5%)
Embryos retained in catheter 1/85 (1.2%) a 2/85 (2.4%) a 10/85 (11.8%) b 10/85 (11.8%) b
Implantation rate 32/219 (14.6%) 40/236 (16.9%) 38/227 (16.7%) 39/229 (17.0%)
Clinical pregnancy rate 22/85 (25.9%) 20/85 (23.5%) 23/85 (27.1%) 25/85 (29.4%)
Miscarriage 3/22 (13.6%) 3/20 (15.0%) 3/23 (13.0%) 2/25 (8.0%)
Ectopic pregnancy 1/22 (4.5%) 1/20 (5.0%) 1/23 (4.3%) 2/25 (8.0%)
Take home baby rate 19/85 (22.4%) 16/85 (18.8%) 19/85 (22.4%) 21/85 (24.7%)
a,b Values with different letters inside the line differed significantly (P<0.05).