1 4th Department of Obstetrics and Gynaecology, Aristotle University of Thessaloniki, Thessaloniki 2 Iakentro Fertility Center, Thessaloniki, Greece, and 3 SIMAF, Van Helmont Hospital, Vilvoorde, Belgium
Dear Sir,
The comments by Biervliet et al. are welcomed, and especially for sharing their extensive experience on embryo transfer. They also provide an important direction for future research. We agree that the mechanical trauma of the endometrium could affect negatively the implantation in IVF cycles. In our paper (Prapas et al., 2001) we cited that this negative effect could be expressed by altering the uterine contractions (Fanchin et al., 1998
; Lesny et al., 1998
), the endometrial maturation process or another unknown mechanism. We believe that the system used by the uterus to refuse the implantation is a complex involving the uterine motility, the endometrial receptivity and the endometrial microenviroment. Obviously there is no evidence as to which factor comes first.
Concerning the pharmacological agents used to reduce uterine contractions, progesterone was used for all our cases. Tsirigotis et al. (2000) have shown that the use of a ß-mimetic (i.e. Ritodrine) in patients presenting increased uterine contractility during the peri-implantation period had a beneficial effect in their IVF cycles (Tsirigotis et al., 2000). We used Ritodrine in 125 IVF cycles in a prospective controlled randomized study but we did not find any statistical difference concerning the implantation and the pregnancy rates.
We agree that research into pharmacological agents, which have the potential to control the endometrial maturation process and to reduce uterine contractions during the peri-implantation period, should be encouraged in order to ameliorate our IVF pregnancy rates.
Notes
4 E-mail: iakentro{at}otentet.gr
References
Fanchin, R., Righini, C., Olivennes, F., Taylor, S., de Ziegler, D. and Frydman, R. (1998) Uterine contractions at the time of embryo transfer alter pregnancy rates after in-vitro fertilization. Hum. Reprod., 13, 19681974.[Abstract]
Lesny, P., Killick, S.R., Tetlow, R.L., Robinson, J. and Maguiness, S.D. (1998) Embryo transfercan we learn anything new from the observation of junctional zone contractions? Hum. Reprod., 13, 15401546.[Abstract]
Prapas, Y., Prapas, N., Hatziparasidou, P., Vanderzwalmen, P., Nijs, M., Prapa, S. and Vlassis, G. (2001) Ultrasound-guided embryo transfer maximizes the IVF results on day 3 and day 4 embryo transfer but has no impact on day 5. Hum. Reprod., 16, 19041908.
Tsirigotis, M., Pelekanos, M., Gilhespie, S., Gregorakis, S. and Pistofidis, G. (2000) Ritodrine use during the peri-implantation period reduces uterine contractility and improves implantation and pregnancy rates post-IVF. Hum. Reprod., 15, (Abs. Bk 1) O-024 p10.