The technique for human embryo transfer.

In a program of human in vitro fertilization (IVF), the results of 204 attempted intracervical embryo transfers (ETs), using a variety of catheters in three trials over 18 months, have been analyzed for the ease of transfer and pregnancy rate. In nulliparous patients, transfers were more difficult than in multiparous patients; and a closed-end Teflon catheter was found to be more easily passed through the smaller cervical canal than an open-end catheter. The overall pregnancy rate was 17% (March 1980 to August 1981) and was not related to catheter type, although when chemical pregnancies were excluded, it was found that transfers using open-end catheters were more successful. The transfer procedure developed finally for routine use incorporates a consideration of these results.