Newsletter

Table of Contents

15.05.2000

Newsletter No. 3

ICSI: the site of injection is important.
ICSI: congenital malformations
Pregnancy rate in IVF with three to five days of embryo culture
IVF/ICSI: Pregnancyrate following transfer of two or three unselected embryos

1. ICSI: the site of injection is important
During the procedure intracytoplasmatic sperm injection intracellular structures such as the spindle within the vicinity of the first polar body should not be vulnerated. On the other side, the sperm should be deposited as close as possible to the maternal genetic material which is close to the spindle apparatus. In order to find the optimal place of sperm deposition a study was undertaken (Blake et al., 2000) with various placements of the polar body during ICSI. It was found that the rate of resulting high quality embryos was highest, when the polar body was placed at 7 band 11 oâ€™clock with the injection of the sperm into the oocyte being performed at 3 oâ€™clock. Using this guideline also the implantation rate tended to be increased over other sites of sperm injection.

Blake M, Garrisi J, Tomkin G, Cohen J (2000) Sperm deposition during ICSI affects fertilization and development. Fertil Steril. 73: 31-37

Talansky BE, Malter HE, Cohen J (1991) The preferential site of sperm-egg fusion in mammals. Mol. Reprod. Dev. 28: 183-188

2. ICSI: congenital malformations

New Swedish data confirm previously data of other groups that ICSI does not increase congenital malformation. An increased incidence of hyposoadias was however associated with ICSI. An inherited background of hypospadias associated with a genetic basis of low sperm count is discussed. The potential role of endocrine disruptors in inducing low sperm count and hypospadias is not discussed by the authors.

Wennertholm UB, Bergh C, Hamberger L, Lundin K, Nilsson L, Wikland M, KÃ¤llen B (2000 Incidence of congenital malformations in children born after ICSI. Hum. Reprod. 15: 944-948

3. Pregnancy rate in IVF with three to five days of embryo culture.

Embryo transfer has been recently delayed from two to up to five days of embryo culture. In a retrspective study, the implantation rate per embryo on days three, four and five was 17.9, 22.2 and 25.7%, respectively, if with > 8 cell embryos, cavitating morula and blastocysts, respectively, the most advanced stages on these respective days were transfered. Less advanced stages yielded poorer results. Only 41% of the embryos reached the blastocyst stage. Therefore, there was, with 25.3, 25.8 and 27.8% respectively, no difference in the overall pregnancy rate with respect to the duration of embryo culture .

Huisman GJ, Fauser BCJM, Eijkemans MJC, Pieters MHCE (2000) Implantation rates after in vitro fertilization and transfer of a maximum of two embryos that have undergone three to five days of culture. Fertil. Steril. 73: 117-122

4. IVF/ICSI: Pregnancy rate following the transfer of two or three unselected embryos

The German embryo protection law does not allow the transfer of selected embryos. Only as many embryos as are intended to be transferred (maximum three) are allowed to be generated. Therefore, the selection has to be done in the PN-stage. In order to avoid triplet pregnancies ther transfer of only twop embryos is recommended. It was therefore of interest top study whether or not the transfer of only two unselected embryos reduces the pregnancy rate versus the transfer of three unselcetd embryos. In a retrospective study it could be shown that the transfer of three unselected embryos taken out of a cohort of in the mean 7.27 PN resulted in a pregnacy rate of 28.6 per embryo transfer, while the transfer of two embryos taken from a cohort of in the mean 6.81 PN-stages resulted in a pregnancy rate of 25.2 % per embryo transfer. The ongoing pregnancy rates with 22.5 and 22.0%, respectively, did not differ between the two groups.

Ludwig M, SchÃ¶pper B, Katalinic A, Sturm R, Al-Hasani S, Diedrich K (2000) Experience with the elective transfer of two embryos under the conditions of the German embryo protection law: results of a retrospective data analysis of 2573 transfer cycles. Hum. Reprod. 15: 319-324

Gerhard Leyendecker