Birth of a baby conceived from frozen oocytes of a 40-year-old woman

State of the art in assisted reproductive technologies for patients with advanced maternal age

According to the World Health Organization, the female reproductive age lasts up to 49 years, but problems with the realization of women's reproductive rights may arise much earlier. Significant numbers of factors affect the state of reproductive health: socioeconomic, ecological, lifestyle features, the level of medical literacy, and the state of the organization and medical care quality. Among the reasons for fertility decline in advanced reproductive age are the loss of cellular receptors for gonadotropins, an increase in the threshold of sensitivity of the hypothalamic-pituitary system to the action of hormones and their metabolites, and many others. Furthermore, negative changes accumulate in the oocyte genome, reducing the possibility of fertilization, normal development and implantation of the embryo and healthy offspring birth. Another theory of ageing causing changes in oocytes is the mitochondrial free radical theory of ageing. Taking into account all these age-related changes in gametogenesis, this review considers modern technologies aimed at the preservation and realization of female fertility. Among the existing approaches, two main ones can be distinguished: methods allowing the preservation of reproductive cells at a younger age using ART intervention and cryobanking, as well as methods aimed at improving the basic functional state of advanced-age women's oocytes and embryos.

Cryo-survival, fertilization and early embryonic development of vitrified oocytes derived from mice of different reproductive age

PURPOSE

to evaluate the effect of female reproductive age on oocyte cryo-survival, fertilization and the subsequent embryonic development following vitrification using the mouse model in order to address the question of how maternal reproductive age is related to fertility preservation.

METHODS

oocytes were collected from mice of different reproductive age: (1) 8-10 weeks, (2) 16-20 weeks, (3) 32-36 weeks, and (4) 44-48 weeks. Following vitrification and warming, the oocytes in each group were assessed for cryo-survival, fertilization and embryonic development as well as for the quality of blastocysts. Fresh oocytes without undergoing vitrification were used in each age group as controls.

RESULTS

the mean number of oocytes retrieved following superovulation was found to reduce significantly (P < 0.05) in mice from 32-36 weeks of age (18.1 ± 8.5) compared with 8-10 weeks of age (26.8 ± 9.8) and 16-20 weeks of age (23.9 ± 4.2) respectively. The cryo-survival rate of oocytes was reduced significantly (P < 0.05) in mice of 44-48 weeks of age (90.4% ± 7.9) compared with the other 3 groups (98.8% ± 2.1, 98.0% ± 3.3 and 98.5% ± 2.2, respectively). The cleavage rate of vitrified oocytes declined significantly following the increase in maternal age in mice of 32-36 weeks of age (69.7% ± 20.8) forward (63.6% ± 9.2). However, no significant difference in the cleavage rate was found among the control groups of different maternal ages. The rate of embryo development to the blastocyst stage in the vitrified oocytes also significantly declined following the increase in maternal age (71.8% ± 8.8, 66.4% ± 10.7, 64.2% ± 17.4 and 4.1% ± 8.3 respectively). There were no such differences in the rates of embryo development to the blastocyst stage among the control groups following the increase in maternal age (75.9% ± 12.2, 79.5% ± 28.9, 70.2% ± 17.4 and 69.3% ± 19.0 respectively). However, the quality of blastocysts produced from 32-36 weeks and 44-48 weeks of ages was significantly poor in term of total cell numbers and the ratio of inner cell mass(ICM) / trophectoderm (TE) compared to younger age in both vitrified and control groups

CONCLUSIONS

cryo-survival of oocytes following vitrification and warming procedures is associated with female reproductive age. There is a more negative impact on the oocytes following vitrification and warming with the increase of maternal age.