Newsletter

Table of Contents

25.07.2007

Newsletter No 4/2007

Risk of monozygotic twinning with blastocyst transfer.
Endometriosis and the genetic polymorphisms of aryl hydrocarbon receptor repressor and glutathione-S-transferase T1 genes
Ovarian reserve and uterine artery embolization.
Blastocyst stage and prediction of pregnancy
Bed rest after embryo transfer?.

1. Risk of monozygotic twinning with blastocyst transfer.

The purpose of this retrospective study is to compare the occurrence of monozygotic twinning (MZT) from blastocyst transfer (BT) in our program between an earlier and more recent time period. All pregnancies conceived between March 2002 and December 2005 (N = 932) in our program were compared to pregnancies conceived before March 2002 (N = 554), which were the subject of a previous study. The incidence of MZT with day 3 embryo transfer and BT were compared between the study and control groups. During the study period, the rate of MZT was not significantly different for BT at 2.3% (9/385) compared to day 3 embryo transfer at 1.8% (10/547). This rate of 2.3% for BT was significantly lower than the rate of 5.6% (11/197) reported at our institution for BT before March 2002. Our study suggests that the risk of MZT with BT is significantly lower in the more recent time period and is in the range of what is seen with cleavage stage transfer. It is likely that improvements in culture systems as experience is gained with BT played a role.

Moayeri SE, Behr B, Lathi RB, Westphal LM, Milki AA. Risk of monozygotic twinning with blastocyst transfer decreases over time: an 8-year experience. Fertil Steril. 2007 May;87(5):1028-32.

2. Endometriosis and the genetic polymorphisms of aryl hydrocarbon receptor repressor and glutathione-S-transferase T1 genes

This study was performed to determine whether genetic polymorphisms of aryl hydrocarbon receptor repressor (AhRR), glutathione-S-transferase M1 (GSTM1) and glutathione-S-transferase T1 (GSTT1) are associated with susceptibility to advanced stage endometriosis in a Korean population. This study comprised 316 women with advanced stage endometriosis and 256 control women without endometriosis. Genotyping of the AhRR codon 185 was performed by real-time polymerase chain reaction (PCR) analysis. GSTM1 and GSTT1 genotyping for gene deletions were carried out by multiplex PCR analysis. G allele frequency at codon 185 of AhRR was increased in patients with endometriosis (P = 0.047), and there was a trend for an association of C/G + G/G genotypes with risk of endometriosis (P = 0.06). The proportion of null mutation at GSTT1 also tended to increase (P = 0.06) in patients with endometriosis, whereas there was no difference in the genotype distribution of GSTM1 genes. Analyzing AhRR and GSTT1 together, we found that patients with high-risk genotypes at both loci have increased risk of endometriosis, compared with patients without high-risk genotypes (P = 0.015). These findings suggest that the AhRR codon 185 and GSTT1 polymorphisms are associated with the risk of advanced stage endometriosis.

Kim SH, Choi YM, Lee GH, Hong MA, Lee KS, Lee BS, Kim JG, Moon SY. Association between susceptibility to advanced stage endometriosis and the genetic polymorphisms of aryl hydrocarbon receptor repressor and glutathione-S-transferase T1 genes. Hum Reprod. 2007 Jul;22(7):1866-70.

3. Loss of ovarian reserve after uterine artery embolization: a randomized comparison with hysterectomy.

Ovarian failure as a complication of uterine artery embolization (UAE) for symptomatic uterine fibroids has raised concerns about this new treatment modality. We investigated the occurrence of ovarian reserve reduction in a randomized trial comparing UAE and hysterectomy by measuring follicle stimulating hormone (FSH) and anti-Mullerian hormone (AMH). A total of 177 pre-menopausal women with menorrhagia due to uterine fibroids were included (UAE: n = 88; hysterectomy: n = 89). FSH and AMH were measured at baseline and at several time-points during the 24 months follow-up period. Follow-up AMH levels were also compared to the expected decrease due to ovarian ageing during the observational period. FSH increased significantly compared to baseline in both groups after 24 months follow-up (within group analysis: UAE: + 12.1; P = 0.001; hysterectomy: + 16.3; P < 0.0001). No differences in FSH values between the groups were found (P = 0.32). At 24 months after treatment the number of patients with FSH levels > 40 IU/l was 14/80 in the UAE group and 17/73 in the hysterectomy group (relative risk = 0.75; P = 0.37). AMH was measured in 63 patients (UAE: n = 30; hysterectomy: n = 33). After treatment AMH levels remained significantly decreased during the entire follow-up period only in the UAE group compared to the expected AMH decrease due to ageing. No differences were observed between the groups. This study shows that both UAE and hysterectomy affect ovarian reserve. This results in older women becoming menopausal after the intervention. Therefore, the application of UAE in women who still wish to conceive should only be considered after appropriate counselling.

Hehenkamp WJ, Volkers NA, Broekmans FJ, de Jong FH, Themmen AP, Birnie E, Reekers JA, Ankum WM. Loss of ovarian reserve after uterine artery embolization: a randomized comparison with hysterectomy. Hum Reprod. 2007 Jul;22(7):1996-2005.

4. Blastocyst-stage and prediction of pregnancy.

This retrospective observational study was performed to define and validate metrics of embryo progression and morphology during extended embryo culture and to compare the effects of early cleavage (EC) vs. blastulation stages on clinical pregnancy. The study included one 1292 sperm injection and 842 IVF blastocyst-transfer cycles. The embryo progression index (EPI) was calculated as the area under the curve of total cell number (TCN) over time, by using observed TCN for cleavage-stage embryos and estimated blastocyst TCN according to morphology. The EPI from days 1-3 measured early cleavage, and blastulation was assessed by EPI over extended embryo culture. Blastocyst morphology was converted into numerical blastocyst quality scores (BQSs). Receiver operating characteristic curve analysis was used to evaluate predictors for clinical pregnancy. Per-cycle mean EPI and mean BQS for all embryos developing into blastocysts, as well as mean BQS of the transferred embryos, were significant predictors of clinical pregnancy in intracytoplasmic sperm injection and IVF cycles. Mean EPI for days 1-3 did not predict outcome. Early cleavage is a putative marker of embryo quality. Late-stage embryo development is more sensitive and specific in predicting clinical pregnancy than is early cleavage, supporting the use of extended embryo culture for embryo selection. The embryo progression index and BQS may also be used for this purpose.

Rehman KS, Bukulmez O, Langley M, Carr BR, Nackley AC, Doody KM, Doody KJ Late stages of embryo progression are a much better predictor of clinical pregnancy than early cleavage in intracytoplasmic sperm injection and in vitro fertilization cycles with blastocyst-stage transfer. Fertil Steril. 2007 May;87(5):1041-52.

5. Bed rest after embryo transfer?

This is a randomized controlled trial in women undergoing IVF to determine whether bed rest after embryo transfer leads to improved pregnancy rates (PR). Patients undergoing 164 cycles of IVF were randomized to 30 minutes of bed rest after embryo transfer or immediate discharge from the clinic. Clinical PR defined by visualized fetal heart beat and ongoing PR defined by viable intrauterine gestation beyond 11 weeks. The clinical and ongoing PR for both groups were 50% and 46.3%, respectively, with no statistically significant difference between the two groups. Thirty minutes of bed rest after embryo transfer does not improve PR.

Purcell KJ, Schembri M, Telles TL, Fujimoto VY, Cedars MI. Bed rest after embryo transfer: a randomized controlled trial. Fertil Steril. 2007 Jun;87(6):1322-6.

Gerhard Leyendecker