The effect of ultrasound (US) guided embryo transfer (ET) and the choice of catheter on the outcome of IVF.

Abstract

Objective: Although there have been important improvements in respect to ovulation induction, fertilization and embryo culture in assisted reproduction, embryo implantation remains the rate-limiting step in the success of IVF. The main factor that affect embryo implantation, besides embryo quality and uterine receptivity, is the technique of embryo transfer. The use of US and the type of transfer catheters are the two most frequently cited factors that contribute to the success of ET, however, their role is disputed, especially, because of the scarcity of well designed prospective studies published. The aim of the present study was, therefore, to compare three popular ET catheters and the use of US guidance during embryo transfer. Design: A prospective, randomized and presently still ongoing study involving 109 ICSI-IVF treatment cycles. The cases were allocated into three groups, according to the type of catheter used in embryo transfer: 1, Wallace catheter (39 cycles); 2 Cook soft (26 cycles), and ultra-soft Frydman (44 cycles). Patients in all the three groups were further divided randomly into two groups depending whether ET was performed with US guidance (total of 69 cycles) or without (total of 40 cycles). Materials/Methods: In all cases ICSI was performed and embryo transfers were done on day 3 always by the same persons. Clinical and laboratory parameters, including patients’ age, fertilization rates, embryo morphology, pregnancy and implantation rates were calculated and compared for all the groups using the one-way ANOVA and the chi-square tests whenever applicable. Results: The mean age of the female patients, fertilization rate, the number and quality of embryos transferred and abortion rates were not significantly different in any of the groups compared irrespective to the type of catheter or to the use of US. The clinical pregnancy (PR) and implantation rates (IR) were higher (P = 0.02) when ET was done with Wallace catheter (46% and 21%) as compared to the other two groups (Cook—19% and 9% and Frydman—23% and 12%). The use of US during ET was not correlated significantly with IVF outcome on the total population. However, when ET was performed with Wallace catheter (but not with Cook or Frydman) clinical PR and IR were higher (P = 0.01) using US (52% and 25%) than without US (30% and 7%). When IVF outcome was compared excluding transfers with US guidance, clinical PR and IR were no longer different in respects of the three ET catheters. Conclusions: Although there were no differences in the age of patients and in the laboratory parameters between any of the groups, the clinical pregnancy and implantation rates were significantly higher when ET was performed with Wallace catheter. The use of US did not improve IVF outcome on the total population, however, only in patients using Wallace catheter it was associated with a significantly higher clinical PR and IR. These results are suggesting that the technique of embryo transfer including the correct selection of the ET catheter has a major influence on IVF success. The role of the US during ET may be clarified better in the near future as the study develops, however, it seems advantageous to improve further the results when used together with an appropriate catheter.