HARI Unit, Rotunda Hospital, Dublin 1, Ireland e-mail: emocanu@rcsi.ie
Dear Sir,
I congratulate Coroleu et al. for a scientifically valuable study (Coroleu et al., 2002). Without a doubt many clinicians would have changed their practice according to the evidence provided in this paper. Indeed, it appears that mid uterine cavity embryo placement offers the best success rates. It is still debatable whether ultrasound adds to an increase success rate or not. Previously published papers (Coroleu et al., 2000
; Wood et al., 2000
) did not specify if the control group participants (clinical touch technique) had full or empty bladders. For clinicians that perform an anatomically correct embryo transfer without ultrasound, a full bladder is a requirement prior to the procedure. Perhaps it is the full bladder (Sundstrom et al., 1984
) and the appropriate embryo placement rather than the use of ultrasound that increases the success rates.
A very valuable measurement would have been the level of insertion of transfer catheter (marking on the outer sheath visible vaginally) in each of the three groups. It is a big surprise to realise how uniform in size uteri are, and that once you identified the correct catheter marking at the external os, transfers become very efficacious indeed. Is there a place for ultrasound then? I am not convinced.
One more aspect. Studies looking at ideal situations (one clinician performing all transfers) are of theoretical value. Nevertheless, in order to be relevant to our patients and ourselves, studies have to be designed following our day-to-day practice. I thus salute studies where all practitioners working in the clinic perform the transfers. It will be false to inform our patients of the progress made if the information sources are studies based on ideal clinical situations, only.
References
Coroleu, B., Carreras, O., Veiga, A., Martell, A., Martinez, F., Belil, I., Hereter, L. and Barri, P.N. (2000) Embryo transfer under ultrasound guidance improves pregnancy rates after in-vitro fertilization. Hum. Reprod., 15, 616620.
Coroleu, B., Barri, P.N., Carreras, O. Martínez, F., Parriego, M., Hereter, L., Parera, N., Veiga, A. and Balasch, J. (2002) The influence of the depth of embryo placement into the uterine cavity on implantation rates after IVF: a controlled, ultrasound -guided study. Hum. Reprod., 17, 341346.
Wood, E.G., Batzer, F.R., Go, K.J., Gutmann, J.N. and Corson, S.L. (2000) Ultrasound-guided soft catheter embryo transfers will improve pregnancy rates in in-vitro fertilization. Hum. Reprod., 15, 107112.
Sundstrom, P., Wransby, H., Person, P.H. and Liedholm, P. (1984) Filled bladder simplifies human embryo transfer. Br. J. Obstet. Gynaecol., 91, 506507[ISI][Medline]