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 preg nancy 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 Wal lace catheter or an Erlangen metal catheter. Randomization was also applied within the same groups for embryo transfer at 48 h and 72 h post-inseminat ion, Fifty patients randomly selected from each group were subjected to spe culum examination 15 min following embryo transfer, during which any fluid leaking from the cervix was examined for the presence of embryos. In five p atients a transvaginal-transmyometrial transfer was performed. The pregnanc y rate appeared to be slightly higher in patients who had their embryos tra nsferred at 72 h than in those patients who had their transfers at 48 h, bu t 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 cer vical 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 em bryos trapped compared with those of the Erlangen group (P = 0.0007). The p regnancy rate per embryo transfer was apparently higher in the Erlangen gro up than in the Wallace group but this difference was not significant. In ei ght (16%) patients of the Wallace group, 1-3 embryos were found in the flui d sucked from the external os, compared with three (6%) patients in the Erl angen group, but again this difference was not significant. In 92% of patie nts who became pregnant, the transfer procedure was smooth and easy. Succes sful embryo transfer was not influenced by the time of transfer postinsemin ation. The choice of catheter did not affect pregnancy rate. In cases in wh ich transcervical transfer is very difficult or impossible, transvaginal-tr ansmyometrial transfer is a viable option. The significance of early or lat e expulsion of transferred embryos into the vagina needs to be addressed in larger controlled studies.