Embryo quality and developmental potential is compromised by age

ICSI outcomes in obstructive azoospermia: influence of the origin of surgically retrieved spermatozoa and the cause of obstruction

BACKGROUND

Spermatozoa can be retrieved from the testis and epididymis of men with obstructive azoospermia (OA) and used for ICSI. However, it is unknown whether the outcome of ICSI depends on the cause of obstruction or the origin of surgically retrieved spermatozoa.

METHODS

A cohort of 171 men with OA and normal spermatogenesis were included in this retrospective study. They were divided into three groups according to the site and origin of obstruction: 83 men had congenital bilateral absence of vas deferens; 55 and 33 had acquired epididymal and deferent duct obstructions, respectively. The outcome of 368 ICSI cycles was determined and compared according to the origin of spermatozoa: epididymal (n = 253) or testicular (n = 115).

RESULTS

Fertilization and clinical pregnancy rates did not differ between spermatozoa of different origin (58.9% versus 51.9% and 22.1% versus 24.3% with epididymal and testicular spermatozoa, respectively). However, the miscarriage rate was significantly higher for testicular spermatozoa (35.7% versus. 12.5% P < 0.05, chi2 test). Findings were similar whatever the aetiology of the OA.

CONCLUSION

This study suggests that the use of testicular spermatozoa, even those generated during normal spermatogenesis, alters embryonic development and that epididymal spermatozoa should be preferentially used, irrespective of the aetiology of OA.

Optimum number of embryos to transfer in women more than 40 years of age undergoing treatment with assisted reproductive technologies

OBJECTIVE

To determine whether increasing the number of embryos transferred beyond five increases pregnancy rates in women aged > 40 years.

DESIGN

Retrospective analysis of cycles performed between January 1998 and July 2003.

SETTING

University-affiliated teaching hospital.

PATIENT(S)

Women aged > 40 years undergoing a fresh cycle with a day-3 ET (n = 863).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Pregnancy, chemical pregnancy, miscarriage rates, number of viable fetuses at 12 weeks' gestation, live birth rates, and number of babies delivered.

RESULT(S)

Compared with patients with fewer than five embryos transferred, those having five or more embryos transferred had significantly increased pregnancy rates and live birth rates, more viable fetuses at 12 weeks, and significantly decreased miscarriage rates. None of these outcome variables differed between the five-embryo and more-than-five-embryo groups. There were no differences in outcome when only five embryos were transferred, regardless of whether five or more than five embryos were available. The number of embryos transferred did not significantly influence multiple birth rates.

CONCLUSION(S)

The present study demonstrates that in women aged > 40 years, five embryos is the optimum number to transfer, and transferring more than five does not confer any additional benefit to clinical outcome.

Likelihood of natural conception following treatment by IVF

PURPOSE

To predict the ongoing likelihood of natural conception, when a couple has ceased to try to conceive by assisted conception.

METHODS

A postal questionnaire survey obtained information on further attempts to conceive and have a baby, either without treatment or by treatment elsewhere.

RESULTS

From a response rate of 44%, there were 116 couples who fulfilled the study criteria. The data presented are based on this group. The overall likelihood of conception was 18%. Cumulative results were analysed up to 3 years following treatment. Univariate analysis showed that likelihood of conception was affected by infertility diagnosis (p = 0.024), woman's age (> 38 years; p < 0.005) (negatively) and duration of infertility (< 3 years; p < 0.005) (positively), while primary infertility did not. Effects of diagnosis and infertility duration were confirmed by multivariable analysis, controlling for age and primary infertility. These latter variables had no independent effect.

CONCLUSION

The likelihood of natural conception following IVF treatment was determined by duration of infertility and diagnosis; tubal disease in particular was associated with a very poor likelihood of natural conception.

Pregnancy outcome in in vitro fertilization decreases to a plateau with repeated cycles

Clinical pregnancy rate (CPR) and implantation rate (IR) in 1,177 patients who had 1,788 fresh, nondonor, nonPGD IVF cycles were highest in cycle 1, significantly declined in cycle 2, and reached a plateau for cycles 3-5 at a rate lower than in cycle 2. In patients >38 years of age CPR and IR in cycles 1 and 2 were significantly lower than in younger patients, but there was no decline in CPR or IR with advancing IVF attempts.

The derivation of two additional human embryonic stem cell lines from day 3 embryos with low morphological scores

BACKGROUND

Immune rejection can lead to the failure of human embryonic stem cell (hES cell) transplantation. One approach to address the problem is to establish hES cell line banks. Due to the limited source of human embryos and to ethical reasons, the hES cell lines are not readily available. This study was undertaken to determine whether discarded day 3 embryos with low morphological scores could develop into blastocysts and produce hES cell lines.

METHODS

A total of 130 day 3 embryos with low morphological scores were cultured to blastocyst stage, and inner cell masses (ICM) were isolated by immunosurgery. Colonies derived from the ICM were passaged every 4-7 days and evaluated for cell surface markers, differentiation potentials and karyotypes.

RESULTS

A total of 19 blastocysts were obtained from 130 embryos (quality score <16), which resulted in the formation of 10 ICM, and two cell lines. Both cell lines satisfied the criteria that characterize pluripotent hES cells.

CONCLUSION

Our results suggest that a subset with poor quality day 3 embryos judged on the basis of morphological assessment can form blastocysts and give rise to hES cell lines.

Low-dose aspirin does not improve ovarian responsiveness or pregnancy rate in IVF and ICSI patients: a randomized, placebo-controlled double-blind study

BACKGROUND

Poor ovarian and endometrial responses to gonadotrophin stimulation in assisted reproduction techniques lead to decreased pregnancy rates. The aim of the present study was to test the hypothesis that low-dose aspirin started prior to controlled ovarian stimulation improves ovarian responsiveness, pregnancy rate (PR) and pregnancy outcome.

METHODS

A total of 374 women who were to undergo IVF/ICSI were randomized to receive 100 mg of aspirin (n=186) or placebo (n=188) daily. Treatment was started on the first day of controlled ovarian stimulation. It was continued until menstruation or a negative pregnancy test. Pregnant women continued the medication until delivery. The main outcome measures were the number of oocytes, number and quality of embryos, the clinical PR and pregnancy outcome.

RESULTS

The mean (+/-SD) number of oocytes (12.0+/-7.0 versus 12.7+/-7.2), the total mean number of embryos (5.82+/-4.35 versus 5.99+/-4.66), the mean number of top quality embryos (0.99+/-1.39 versus 1.18+/-1.51) and the number of embryos transferred (1.64+/-0.64 versus 1.63+/-0.71) did not differ in the aspirin and placebo groups. Between the aspirin and placebo group, there was no statistically significant difference in clinical PR per embryo transfer (25.3%, n=44 out of 174 versus 27.4%, n=48 out of 175) or clinical PR per cycle initiated (23.7% versus 25.5%). Birth rate per embryo transfer did not differ significantly between the aspirin (18.4%) and placebo (21.1%) groups. The incidence of poor responders [12 (6.5%) versus 13 (6.9%)] was similar in both groups.

CONCLUSIONS

The present results indicate that low-dose aspirin treatment does not have any beneficial effect on ovarian responsiveness, PR and pregnancy outcome in unselected women undergoing IVF/ICSI.

Maternal Factors Controlling Blastomere Fragmentation in Early Mouse Embryos1

Interactions between sperm and egg are required to maintain embryo viability and cellular integrity. Differential transcriptional activities and epigenetic differences that include genomic imprinting provide mechanisms by which complementary parental genome functions support early embryogenesis. We previously showed that cytofragmentation can be influenced by the specific combination of maternal and paternal genotypes. Using maternal pronuclear transfer in mouse embryos, we examined the cellular basis for the maternal genotype effect. We found that the maternal genotype effect is predominantly controlled by the maternal pronucleus, with a lesser role played by the ooplasm. This effect of the maternal pronucleus is sensitive to alpha-amanitin treatment. The effect of the maternal component of the embryonic genome on cytofragmentation constitutes the earliest known effect of the embryonic genome on mammalian embryo phenotype. The results also indicate that clinical procedures seeking to define or manipulate oocyte quality in humans should take into account early effects of the embryonic genome, particularly the maternal genome.

The effect of advancing paternal age on pregnancy and live birth rates in couples undergoing in vitro fertilization or gamete intrafallopian transfer

OBJECTIVE

This study was undertaken to determine effects of male aging on sperm parameters, fertilization, pregnancy, and live birth rates among in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) couples. The impact of female age was also investigated.

STUDY DESIGN

Prospective study was made up of 221 IVF and GIFT couples.

RESULTS

Pregnancy rates declined as the male subjects aged. Each additional year of paternal age was associated with 11% increased odds (P=.007) of not achieving a pregnancy, and 12% odds (P=.01) of not having a successful live birth. For first-time IVF/GIFT recipients, each additional year of paternal age was associated with a 5% increased odds of not achieving a pregnancy, whereas for repeaters it was 40% (P=.01). Advancing maternal age was associated with decreased numbers of oocytes retrieved or fertilized. Women 40 years or older compared with younger than 35 years had greater than 4-fold risk of not becoming pregnant, and greater than 20-fold risk of not achieving a live birth.

CONCLUSION

Advancing paternal (and maternal) age had a deleterious effect on IVF and GIFT outcomes.

Cycle characteristics of day 3 embryo transfers with 4-cell embryos only

PURPOSE

Patient and cycle characteristics of day 3 transfers with developmentally lagging 4-cell embryos only were analyzed and related to the outcome of a live birth.

METHODS

Day 3 transfers with either 4-cell embryos only (study group; n = 138) or 8-cell embryos only (control group; n = 282) were compared retrospectively.

RESULTS

The total dose of FSH per treatment was higher, while the number of oocytes, zygotes, and transferred embryos was lower in the study group cycles compared to controls. The implantation, pregnancy, and live birth rates were dramatically lower in the study group compared to the control group. In the study group, the few cycles resulting in a live birth were characterized by a normal ovarian response to stimulation, similar to that of control group cycles with- or without a live birth.

CONCLUSIONS

In cycles characterized by intensive ovarian stimulation, but poor response, the chance for a live birth is extremely low after day 3 transfer of 4-cell embryos.

Day 3 and day 5 morphological predictors of embryo viability

Controlling multiple pregnancies in patients undergoing artificial reproductive procedures requires consideration of single embryo transfers. Therefore, refinements for embryo evaluation are needed that select for the most developmentally competent embryo. The present study was designed to identify day 3 and day 5 morphological predictors of viability following transfers in which the morphology and fate of each embryo was precisely determined. Assessments on day 3 included cell number, and the extent of fragmentation and asymmetry, and on day 5, the developmental stage. Embryos resulting in a viable fetus at 11 weeks gestation were considered developmentally competent. The relationships among individual and collective embryo morphological characteristics were evaluated. Analysis of the interactions among morphological characteristics of embryos transferred on day 3 enabled identification of a multivariable selection order. Assessment of day 5 embryos revealed that expanding and expanded blastocysts exhibited comparable developmental potential that was superior to that of either morulae or early blastocysts. However, expanding or expanded blastocysts derived from 7-cell or 8-cell embryos were developmentally superior to those derived from other cleavage stages, regardless of fragmentation or asymmetry. Collectively, these findings further understanding of morphological predictors of viability, thereby improving the ability to select the most viable embryo for transfer.

Commuting the death sentence: how oocytes strive to survive

Programmed cell death claims up to 99.9% of the cells in the mammalian female germ line, which eventually drives irreversible infertility and ovarian failure - the menopause in humans. New insights into the mechanisms that underlie germ-cell apoptosis have been provided by the study of oocyte death in lower organisms and in genetically manipulated mice that lack apoptosis-regulatory proteins. With new therapeutic tools to control fertility, oocyte quality and ovarian lifespan on the horizon, understanding how and why the female body creates, only to delete, so many germ cells is imperative.