The impact of embryo quality on pregnancy outcome in elderly women undergoing in vitro fertilization-embryo transfer (IVF-ET)

Diagnosis of inherited disease before implantation

The diagnosis of inherited disease in affected embryos before implantation is now possible using in vitro fertilization (IVF), embryo biopsy and DNA analysis. This enables pregnancies to be established with unaffected embryos following transfer to the uterus avoiding the possibility of terminating a pregnancy diagnosed as affected later in gestation. Pregnancies have been established with female embryos in women carrying X-linked recessive genetic defects affecting boys by identifying the sex of embryos either by DNA amplification of Y-specific sequences or by dual fluorescent in situ hybridization (FISH) with X- and Y-specific probes to interphase nuclei. The predominant ΔF508 deletion causing cystic fibrosis (CF) has also been detected by DNA amplification from single cells and the first pregnancy and birth of a child successfully screened for a single gene defect achieved. The prospects for applying preimplantation diagnosis to other chromosomal and single gene defects are reviewed.

Role of embryo quality in predicting early pregnancy loss following assisted reproductive technology

Early pregnancy loss (EPL) significantly reduces the initial success rate of assisted reproduction treatments and increases the psychological burden on the patient. The aim of the current study was to investigate the association between embryo quality and EPL in IVF. A retrospective study of 1471 women undergoing IVF between July 2000 and October 2004 was performed. Multivariate logistic regression models evaluated the effect on EPL of the woman's age, type and cause of infertility, endometrial thickness on the day of oocyte retrieval, performance of intracytoplasmic sperm injection, number of transferred embryos, embryo quality as assessed by the number of blastomeres in the leading transferred embryo at day 3, and the percentage of fragmentation. The 2902 oocyte retrieval-embryo transfer cycles resulted in 816 pregnancies (28.1%; 705 women) constituting the study cohort. Of these, 259 pregnancies (31.7%) ended in EPL and 557 (68.3%) in ongoing pregnancies. EPL risk was significantly associated with advanced (>35 years) maternal age (OR=1.53; 95% CI 1.12-2.09) and five or fewer blastomeres in the leading embryo transferred at day 3 (OR=1.82; 95% CI 1.16-2.85). In conclusion, the quality of transferred embryos, as assessed by the total number of blastomeres in the leading transferred embryo, and maternal age are predictors of EPL.

Features associated with reproductive ageing in female rhesus monkeys

BACKGROUND

The specific aims were to determine the effects of maternal age on the meiotic and developmental competence of oocytes and incidence of chromosomal anomalies in oocytes from a population of fertile rhesus monkeys.

METHODS

Monkeys were divided into two age groups (4-15 and 16-26 years of age) and underwent ovarian stimulation for collection of oocytes.

RESULTS

In the older, compared with younger, monkeys, serum basal concentrations of FSH were elevated (P < 0.05), peak concentrations of estradiol during a stimulation cycle were diminished (P < 0.05), and mean numbers of oocytes retrieved following ovarian stimulation were markedly (P < 0.05) reduced. There were no significant maternal age-related impairments in oocyte maturation, fertilization or blastocyst development. Both abnormal numbers of whole chromosomes, as well as free chromatids, were detected in a limited number of rhesus oocytes.

CONCLUSIONS

Similarities between female rhesus monkeys and women in several features associated with reproductive ageing, in conjunction with our ability to perform IVF and other assisted reproductive techniques in monkeys, demonstrate the suitability of these animals for studies on human reproductive ageing and maternal age-related infertility. Although maternal age-related impairments in oocytes were not evident prior to implantation, further studies may reveal more subtle impairments, manifested during post-implantation development.

Assessing fertility in women of advanced reproductive age

Reproductive capacity in women declines dramatically beyond the fourth decade of life. Oocyte quality seems to be the primary determinant of reproductive potential, although age-related uterine changes may also contribute. Underlying reasons for reproductive decline in women remain unclear, and both ovarian and neuroendocrine mechanisms have been proposed.A number of age-related endocrinologic changes precede menopause and predict diminished reproductive capacity. Thus, "ovarian reserve" screening may identify patients in whom attempts at conventional assisted reproduction is warranted before proceeding with ovum donation. Techniques to preserve the maternal genetic contribution to offspring (in lieu of egg donation), including germinal vesicle transfer and donor ooplasm, are under investigation.

An analysis of the effect of age on implantation rates

PURPOSE

To evaluate implantation rate as a function of age.

METHODS

A total of 1621 consecutive cycles of IVF were evaluated for implantation as a function of age at The New York Hospital/Cornell Medical Center.

RESULTS

An overall implantation rate of 23.3% (1328/5691) was found. The implantation rate as a function of age decreased in a nonlinear fashion. Implantation remained constant until the age of 35 and then decreased in a significantly, linear fashion by 2.77% per year (P < 0.001, R2 = 0.975). A formula to predict implantation rates for a given age was developed: Implantation rate = -119.352 + (9.985 x Age - (0.164 x Age2)).

CONCLUSIONS

We have demonstrated that implantation rates remain constant until the age of 35 at which time a linear decrease of 2.77% per year is observed.

Endometrial preparation: lessons from oocyte donation

OBJECTIVE

To gain insight into the physiology of human endometrial development after artificial preparation with estrogen (E) and P, before oocyte donation.

DESIGN

Review and analysis of relevant studies published in the last decade, identified through the literature and Medline searches.

RESULTS

Oocyte donation represents a unique in vivo experimental model in the human that permits the study of endometrial development under controlled variable conditions. Early studies have shown that adequate endometrial preparation can be achieved by sequential E and P only. The successful implementation of the simplified approach to oocyte donation demonstrated that satisfactory endometrial receptivity is not dependent on incremental administration of E and P and similarly can be achieved by fixed dosages of these steroids. Moreover, numerous clinical oocyte donation studies have shown that both physiologic and supraphysiologic levels of E and P have resulted in good endometrial development and pregnancy rates, underlining the relative insensitivity of the endometrium to extreme hormonal conditions. In addition, it has been clarified that the endometrium is tolerant of some manipulations during the follicular phase. Contrary to morphological studies that demonstrated preservation of endometrial preparation after luteal E depletion, preliminary evidence suggests that the functional capacity of the endometrium could be affected adversely.

CONCLUSION

In contrast to early oocyte donation studies, which indicated a correlation between morphologic integrity and functional capacity of the endometrium, some evidence presented in this review demonstrates that adequate endometrial morphology does not always imply normal endometrial receptivity.

The impact of maternal age on clinical pregnancy and spontaneous abortion in women undergoing in vitro fertilization and gamete intra-fallopian transfer

The age at which women should be advised against proceeding with initial or further infertility treatment is one of the many unresolved questions in this area of women's health and was the subject of investigation in this study. One of the major difficulties in determining the impact of maternal age on outcomes is the practice of researchers (publishing in journals) and infertility practitioners (reporting to national registers) of coding age as a categorical rather than a continuous variable. In this study, groups of younger (< 30 years) and older (> 35 years) women undergoing assisted reproduction treatments were compared with regards to clinical pregnancy and spontaneous abortion rates following in vitro fertilization (IVF) or gamete intra-Fallopian transfer (GIFT). Response to different ovarian stimulation protocols was also assessed for the 2 groups. The significance of the relationship between maternal age, clinical pregnancy rates, spontaneous abortion rates and the type of treatment and stimulation protocol employed, was tested using a series of binomial distributions. The results indicated that maternal age adversely affects both clinical pregnancy rates and rates of spontaneous abortion, when summed across treatments and stimulation protocols. However, while the age/outcome relationship held for IVF, the GIFT by age relationship was not significant. Stimulation protocols using clomiphene citrate (CC) or gonadotrophin agonists (GnRHa) may impact negatively on older women.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute pelvic inflammatory disease after oocyte retrieval: adverse effects on the results of implantation

OBJECTIVE

To determine the impact of pelvic inflammation on the results of IVF after oocyte retrieval.

DESIGN

Retrospective analysis of IVF cycles.

SETTING

IVF Unit, Golda Medical Center, Petah Tikva, Israel.

PATIENTS

Twenty-eight women with a diagnosis of pelvic inflammatory disease (PID) during IVF therapy.

MAIN OUTCOME MEASURE

The pregnancy rate (PR) of IVF cycles complicated by PID after oocyte retrieval was compared with our ongoing IVF results.

RESULTS

All 28 women with PID during IVF treatment did not conceive, despite the high number of oocytes retrieved, fertilized, and transferred. The PR over the same period was 23% to 31%.

CONCLUSIONS

Pelvic infection after IVF treatment might have a detrimental effect on the results of treatment. In an effort to maximize the chances for normal implantation, postponement of ET should be considered when pelvic infection or inflammation is diagnosed.

Age-related decline in female fertility is not due to diminished capacity of the uterus to sustain embryo implantation

OBJECTIVE

To evaluate the contribution of the uterus to age-related reproductive failure in women.

PATIENTS

Thirty-eight ovum donors (30.2 +/- 4.9 years [mean +/- SD]) donating oocytes throughout 102 ovum donations. Fifty-one cycles were documented in "younger" recipients (35.8 +/- 3.1 years) and 51 in "older" recipients (44.0 +/- 3.1 years). The study was prospectively designed; same-cohort oocytes obtained from one young donor during a specific cycle were evenly distributed between "young" and "old" ovum recipients. Use of oocytes from a single source and a unique ovulatory cohort provides strict control over oocyte quality. Uterine age is varied by design, according to the age of the recipient at the time of ET. The role of the aging uterus in the decline of female fertility can be thus isolated and scrutinized.

RESULTS

No significant (NS) difference in the number of ova received (7.9 +/- 3.4 versus 7.0 +/- 3.5), ova fertilized (4.4 +/- 1.5 versus 4.5 +/- 2.3), or embryos transferred (4.1 +/- 1.5 versus 4.1 +/- 1.6) was observed between the < 40 and > or = 40 recipient age groups. A total of 23 pregnancies occurred among the 102 ETs (22.6%). Eleven clinical pregnancies (21.6%) resulting in 10 deliveries were observed in the < 40 recipient age group, and 12 clinical pregnancies (23.5%) leading to 10 deliveries occurred in the > or = 40 recipient age group (NS). The pregnancy loss rates were 9.1% (1 of 11) and 16.7% (2 of 12) for the two recipient age groups, respectively, (NS).

CONCLUSION

The capacity to conceive and to gestate a conception to term when oocyte quality is controlled appears to be independent of uterine aging through the fifth decade of life.

The use of a liquid-phase controlled rate freezing system for the successful cryopreservation of mouse pre-embryos

OBJECTIVES

To investigate the ability of a liquid-phase, controlled-rate freezing machine to generate reproducible freezing gradients with a constant rate of change; temperature fluctuations and heat dissipation during seeding; to assess the viability of mouse pre-embryos exposed to the silicone liquid cooling phase and the rates of survival and viability of mouse pre-embryos cryopreserved using this system.

DESIGN

Freezing gradients were generated from the bath or a sample and compared for reproducibility and slope. Temperature fluctuations and gradients around the freezing chamber and the temperature rises and dissipation during seeding were measured. The toxicity of the silicone polymer freezing-phase was tested with mouse pronuclear pre-embryos. Different developmental stages of mouse pre-embryos were frozen and thawed and survival recorded in vitro and in vivo.

SETTING

Research Laboratories, Sinai Hospital of Baltimore, Baltimore, Maryland.

MAIN OUTCOME MEASURES

The reproducibility of freezing gradients; temperature fluctuations during seeding; and the in vitro and in vivo viability of mouse pre-embryos exposed to the silicone polymer or frozen and thawed.

RESULTS

The freezing gradients generated were constant and reproducible with a constant rate of change; no temperature differences were recorded around the freezing chamber; temperature changes at seeding are minimal and rapidly dispersed. The silicone polymer was nontoxic to mouse pre-embryos and mouse pre-embryos frozen with the system and subsequently thawed are viable both in vitro and in vivo.

CONCLUSIONS

This liquid-phase cryopreservation system is an attractive option for assisted reproductive technologies laboratories because liquid nitrogen is not required for operation, it is reliable, there are small temperature fluctuations during seeding, and it can be kept constantly running.

Prediction of response to controlled ovarian hyperstimulation: a comparison of basal and clomiphene citrate-stimulated follicle-stimulating hormone levels

OBJECTIVE

To test the ovarian reserve in a high-risk population before controlled ovarian hyperstimulation for in vitro fertilization (IVF).

DESIGN

A prospective study comparing the outcome of a clomiphene citrate (CC) challenge test to the outcome of subsequent IVF cycles.

SETTING

Unit for assisted reproductive technology in a university hospital.

PATIENTS, PARTICIPANTS

Ninety-one infertile women with an age of 35 years or more, who had previous ovarian surgery or who had been diagnosed with ovarian endometriosis.

MAIN OUTCOME MEASURE

Relate follicle-stimulating hormone (FSH) levels before and after CC to frequency of cancellation of an IVF cycle because of a poor follicular response.

RESULTS

Twenty-one patients had elevated basal levels of FSH. Thirty-seven patients, including 20 with high basal levels, showed an excessive FSH response to CC with an FSH level after CC above the 95% confidence limit. Clomiphene citrate-stimulated FSH levels correlated better than basal levels with response to controlled ovarian hyperstimulation. An excessive FSH response to CC predicted a poor response outcome of subsequent controlled ovarian hyperstimulation for IVF with 85% accuracy.

CONCLUSION

Follicle-stimulating hormone response to CC predicts subsequent follicular response to controlled ovarian hyperstimulation.

Poor oocyte quality rather than implantation failure as a cause of age-related decline in female fertility

Female fertility declines with advancing age. To establish whether this age-related reproductive failure results from diminished oocyte quality or uterine/endometrial inadequacy we investigated ovum donation in 35 infertile women, aged 40 years or older (mean 42.7 [SE 0.3]) who had failed at attempts at conception with their own (self) oocytes. Oocytes were donated by 29 young individuals (mean age 33.4 [0.7]) undergoing in-vitro fertilisation (IVF). 8 (5.3%) pregnancies were achieved in 150 cycles of ovulation induction with self-oocytes and 2 (3.3%) in 60 such cycles by in-vitro fertilisation (IVF), but none attained viability. By contrast in 50 cycles with donated oocytes 28 (56%) pregnancies and 15 (30%) deliveries were realised (p less than 0.005). The rate of implantation per embryo transferred was higher (14.7%) with donated oocytes than that with self-oocytes (3.3%) (p less than 0.01). To further elucidate the contribution of age to reproductive outcome, pregnancy results were compared between the young donors and older recipients. Both donors and recipients shared oocytes from the same induced cohort. Rates for clinical pregnancy and delivery did not differ between donors (33% and 23%) and recipients (40% and 30%). Our data suggest that the age-related decline in female fertility is attributable to oocyte quality and is correctable by ovum donation. The uterus can adequately sustain pregnancies even when reproductive potential is artificially prolonged into the late 40s.