Transfer technique and catheter choice influence the incidence of transcervical embryo expulsion and the outcome of IVF.

We examined the influence of the procedures used in embryo transfer on pregnancy rates. Over a period of 15 months (Nov. 1996-Jan. 1998), 320 patients were recruited. They were randomized on an alternate basis either to a Wallace catheter or an Erlangen metal catheter. Randomization was also applied within the same groups for embryo transfer at 48 h and 72 h post-insemination. Fifty patients randomly selected from each group were subjected to speculum examination 15 min following embryo transfer, during which any fluid leaking from the cervix was examined for the presence of embryos. In five patients a transvaginal-transmyometrial transfer was performed. The pregnancy rate appeared to be slightly higher in patients who had their embryos transferred at 72 h than in those patients who had their transfers at 48 h, but this difference was not significant in either group. (The ease with which the Erlangen catheter was used compared with that of the Wallace catheter was reflected in a significantly lower incidence of uterine sounding of cervical dilatation and bleeding.) Also there was a significant increase (P = 0.0001) in the mucus attached to the tip of the Wallace catheter and the embryos trapped compared with those of the Erlangen group (P = 0.0007). The pregnancy rate per embryo transfer was apparently higher in the Erlangen group than in the Wallace group but this difference was not significant. In eight (16%) patients of the Wallace group, 1-3 embryos were found in the fluid sucked from the external os, compared with three (6%) patients in the Erlangen group, but again this difference was not significant. In 92% of patients who became pregnant, the transfer procedure was smooth and easy. Successful embryo transfer was not influenced by the time of transfer post-insemination. The choice of catheter did not affect pregnancy rate. In cases in which transcervical transfer is very difficult or impossible, transvaginal-transmyometrial transfer is a viable option. The significance of early or late expulsion of transferred embryos into the vagina needs to be addressed in larger controlled studies.