In vitro fertilization and oocyte donation in women 45 years of age and older

Fetal Motherhood: Toward a Compulsion to Generate Lives?

A scientist at Edinburgh University announced in 1994 that he had removed ovaries from, mouse fetuses and transplanted them, to adult mice. The ovaries released eggs, and conceptions occurred. Although this was not the first such attempt with mice, the study attracted attention because the researcher suggested, that fetal to adult ovarian transplants were a theoretical possibility for humans. If aborted, fetuses were used, as egg sources in assisted conception, a new entity would arise: the never-born genetic mother. Using eggs from aborted fetuses for conception would lead to quixotic and novel family ties. Its use would echo surrogate gestational motherhood, in which a child has both a genetic mother who contributed her egg and a gestational mother who contributed her uterus for gestation and childbirth. With fetal egg use, however, the child's genetic mother would be a never-born fetus without sentience or known, physiology.

Live birth after IVF in a 46-year-old woman

Pregnancies after IVF have been reported in women aged > or =44 years, but nobody older than 45 years at oocyte retrieval delivered. We report a case of birth of a healthy child after IVF in a 46-year-old infertile woman. Ovarian stimulation was performed with clomiphene citrate, 150 mg daily for 5 days. Three oocytes were retrieved and one embryo was replaced. The patient delivered a healthy male infant after Caesarean section at 39 weeks. A successful pregnancy after IVF with homologous oocytes can be achieved in women older than 45 years. At this age IVF is not a cost-effective treatment compared with oocyte donation, but it may be offered in countries in which gamete donation is forbidden.

The promise of post-menopausal pregnancy (PMP)

Postmenopausal pregnancy (PMP) is presented as a means of alleviating women's suffering by helping them realize their wish for a child of their "own." The availability of IVF technology and oocyte donation, both necessary for PMP, create the illusion of unlimited female fertility. The aim of this paper is twofold: (1) to examine the psychosocial, health, and ethical aspects of PMP; and (2) to answer the question of whether PMP's promise of unlimited fertility really offers more personal freedom and control for women. The paper concludes that PMP seems to increase, rather than to decrease, human suffering.

Chromosomal anomalies in human gametes and pre-implantation embryos, and their potential effect on reproduction

This paper reviews the latest data on chromosomal abnormalities in human gametes and embryos. A close relationship between such anomalies and reproduction failure in humans has been postulated, thereby underscoring the importance of ongoing studies into the mechanisms leading to anomalies. Until recently, knowledge of chromosomal anomalies in human gametes and embryos has been limited. Newly developed strategies (in vitro fertilization combined with micromanipulation techniques followed by multicolour fluorescence in situ hybridization, and PCR analyses) allow precise investigation of this problem. This review of the available information on the etiology of chromosomal anomalies indicates that some of the genetic anomalies in human gametes and early embryos result in reproductive failure.

Transvaginal ultrasound-guided oocyte retrieval following FSH stimulation of domestic goats

The objectives of this study were to evaluate different ovarian stimulation protocols on donor goats and to develop a safe, repeatable method for harvesting oocytes from FSH-treated does (Experiment I). Based on the preliminary findings of the first experiment, 32 crossbred does were used in a second experiment (Experiment II), 16 that had not been previously aspirated and 16 that had undergone one previous aspiration, were used to fine tune the procedure. Females were randomly subjected to 1 of the 2 ovarian stimulation protocols: Treatment (A) does were implanted with a norgestomet ear implant. Starting 10 d post-implantation, does were administered FSH daily for 4 d. Does in Treatment (B) were treated similarly to those in (A) but were implanted for only 3 d before starting the FSH injections and implants were not removed prior to aspiration. Using a 2 x 2 factorial arrangement, fresh does (n=16), not previously aspirated, were then further randomly assigned to either a laparoscopic aspiration procedure (LAP) or a transvaginal ultrasound-guided aspiration procedure (TUGA). The LAP procedure was performed using a fiber optics. For the TUGA, the doe was placed in dorsal recumbency, and a 5 MHz human transvaginal transducer, attached to the ultrasound unit, was positioned vaginally for oocyte aspiration. In summary, there was no significant difference among treatment groups for parameters evaluated, with the exception of methods for oocyte collection. The number of follicles detected and oocytes harvested using TUGA (9.5 and 4.3, respectively) was less than for females obtained by LAP (17.4 and 14.4, respectfully). The percentage of oocytes recovered from does subjected to the TUGA (68%), however, was similar to those subjected to the LAP (69%). Unlike donor does subjected to a repeated LAP, there was no evidence of adhesions in donor does from the repeated TUGA group. The TUGA approach to oocyte collection should not be overlooked in an effort to decrease the chances of adhesions in valuable donor goats.

Genetics of oocyte ageing

OBJECTIVES

Correlations between parental age, aneuploidy in germ cells and recent findings on aetiological factors in mammalian trisomy formation are reviewed.

METHODS

Data from observations in human oocytes, molecular studies on the origin of extra chromosomes in trisomies, experiments in a mouse model system, and transgenic approaches are shown.

RESULTS

Errors in chromosome segregation are most frequent in meiosis I of oogenesis in mammals and predominantly predispose specific chromosomes and susceptible chiasmate configurations to maternal age-related nondisjunction. Studies on spindle structure, cell cycle and chromosome behaviour in oocytes of the CBA/Ca mouse used as a model for the maternal age-effect suggest that hormonal homeostasis and size of the follicle pool influence the quality, maturation competence and spindle size of the mammalian oocyte. Predisposition to errors in chromosome segregation are critically dependent on altered cell cycles. Compromised protein synthesis and mitochondrial function affect maturation kinetics and spindle formation, and cause untimely segregation of chromosomes (predivision), mimicking an aged phenotype.

CONCLUSIONS

Altered cell cycles and untimely resolution of chiasmata but also nondisjunction of late segregating homologues caused by asynchrony in cytoplasmic and nuclear maturation appear to be causal to errors in chromosome segregation with advanced maternal age. Oocytes appear to lack checkpoints guarding against untimely chromosome segregation. Genes and exposures affecting pool size, hormonal homeostasis and interactions between oocytes and their somatic compartment and thus quality of follicles and oocytes have the potential to critically influence chromosome distribution in female meiosis and affect fertility in humans and other mammals.

In vitro fertilization in women over 40 years of age. A study on retrospective data for eight years

A retrospective (1987-1995), single-center study was conducted to evaluate the IVF success rate in women who were 40 years and over. Controls were randomly selected patients who were 35 years or younger from the same center. The main evaluation criterion was the number of pregnancies initiated in each group and especially the number of full-term deliveries (take-home baby rate). Differences were considered as statistically significant for P < or = 0.05: A total of 194 IVF attempts in women 40 years or over were compared to 209 attempts in the control group. The mean ages of the two groups was 40.9 vs. 29.3 years (P < 0.001). The duration of follicle stimulation was 12.9 vs. 13.1 days (not significant, NS). The number of ampules was 29.6 vs. 29.2 (NS). Serum estradiol levels were 1435.8 vs. 2020.8 pg/ml (P < 0.001). Oocytes: 4.6 vs. 7.3 (P < 0.001). Embryos: 1.7 vs. 2.8 (P < 0.0001). Full-term deliveries: 3.6 vs. 13.4% (P < 0.05). Better oocyte retrieval was achieved (5.3 vs. 3.3; P = 0.001) in the group that was 40 years or over, but there were no differences in the rate of embryo transfer (1.9 vs. 1.3; NS) and full-term deliveries (4.2 vs. 2.9%) in a long protocol compared to a short one. The results of the study are similar to those found in the literature. Indications for standard IVF without oocyte donation should be carefully thought out and couples should be warned of the low success rate.

Parental age-related aneuploidy in human germ cells and offspring: a story of past and present

Parental age is the most important aetiological factor in trisomy formation in humans. Cytogenetic studies on germ cells reviewed here imply that (i) 2-4% sperm are aneuploid and 8.6% oocytes from IVF are hyperploid (ii) a paternal age effect may exist, and (iii) oocytes of aged women contain precociously separated chromatids in metaphase II. Trisomy data suggest that most aneuploidy is generated during meiosis I of oogenesis and is maternal age-dependent. Trisomy 18 is unique, originating mostly from maternal meiosis II errors. The extra gonosome in 47, XXY derives mostly from a paternal meiosis I error. Trisomy of individual chromosomes may remain low, linearly rise, or exponentially increase with advanced maternal age. Maternal age related trisomies involve achiasmatic and normochiasmate chromosomes, and chromosomes with disturbed recombination and distally located chiasmata. Hypotheses on the origin of the maternal age effect are critically reviewed. One model is presented that relates to altered cell cycle and protein phosphorylation in oocytes of aged mammals and accounts for most of the observed data in humans and in experimental studies. Aneuploidy may thus involve a predetermined component but is possibly also influenced by extrinsic factors reducing oocyte quality or depleting the oocyte pool precociously. Areas of future research are proposed to elucidate (i) the significance of early disturbances in the prenatal ovary, (ii) parameters diminishing the quality of oocytes in dictyate stage, and (iii) mechanisms enabling oocytes to process all chromosomal configurations successfully during later stages of oogenesis. Studies with newly developed and existing animal models appear indispensable to identify exposures affecting chromosome disjunction during meiosis, especially in the aging female.