Chromosomal abnormalities of the embryo are the most common cause of first-trimester pregnancy loss. In this single-center study, we assessed the frequency and the spectrum of chromosomal abnormalities in miscarriages for each year of maternal age from 23 to 44. Cytogenetic data were obtained by conventional karyotyping of 7118 miscarriages in women with naturally conceived pregnancies. Chromosomal abnormalities were identified in 67.25% of miscarriages. The total incidence of chromosomal abnormalities increased with maternal aging; however, its average change for a one-year increase in maternal age differed between age spans, equaling 0.704% in the span from 23 to 37 years and 2.095% in the span from 38 to 44 years. At the age of 38 years, the incidence rate surged sharply by 14.79% up to 79.01% and then increased progressively up to 94% in 44-year-old women. The spectrum of chromosomal abnormalities in miscarriages was the same for each year of maternal age from 23 to 44 years. However, the proportions of particular chromosomal abnormalities differed between karyotypically abnormal miscarriages in younger and older women. The proportions of trisomy 16, polyploidy, monosomy X, mosaic aneuploidies, and structural rearrangements decreased with increasing maternal age. In contrast, the proportions of multiple aneuploidies and regular trisomies 13, 15, 18, 21, and 22 showed an upward trend with maternal aging. To summarize, despite the increase in the total incidence of chromosomal abnormalities in miscarriages with maternal aging, the rate of change differs for younger and older women, being three times lower in the former than in the latter. Moreover, the proportion of some abnormalities in karyotypically abnormal miscarriages shows a steady growth, whereas the proportion of others becomes increasingly low with maternal aging, most probably due to the age-dependent prevalence of different molecular and cellular defects.

The present study investigates telomere length (TL) in dividing chorionic cytotrophoblast cells from karyotypically normal and abnormal first trimester miscarriages and ongoing pregnancies. Using Q-FISH, we measured relative TLs in the metaphase chromosomes of 61 chorionic villous samples. Relative TLs did not differ between karyotypically normal samples from miscarriages and those from ongoing pregnancies (p = 0.3739). However, among the karyotypically abnormal samples, relative TLs were significantly higher in ongoing pregnancies than in miscarriages (p < 0.0001). Relative TLs were also significantly higher in chorion samples from karyotypically abnormal ongoing pregnancies than in those from karyotypically normal ones (p = 0.0018) in contrast to miscarriages, where relative TL values were higher in the karyotypically normal samples (p = 0.002). In the karyotypically abnormal chorionic cytotrophoblast, the TL variance was significantly lower than in any other group (p < 0.05). Assessed by TL ratios between sister chromatids, interchromatid TL asymmetry demonstrated similar patterns across all of the chorion samples (p = 0.22) but significantly exceeded that in PHA-stimulated lymphocytes (p < 0.0001, p = 0.0003). The longer telomere was predominantly present in the hydroxymethylated sister chromatid in chromosomes featuring hemihydroxymethylation (containing 5-hydroxymethylcytosine in only one sister chromatid)—a typical sign of chorionic cytotrophoblast cells. Our results suggest that the phenomena of interchromatid TL asymmetry and its association to 5hmC patterns in chorionic cytotrophoblast, which are potentially linked to telomere lengthening through recombination, are inherent to the development programme. The TL differences in chorionic cytotrophoblast that are associated with karyotype and embryo viability seem to be determined by heredity rather than telomere elongation mechanisms. The inheritance of long telomeres by a karyotypically abnormal embryo promotes his development, whereas TL in karyotypically normal first-trimester embryos does not seem to have a considerable impact on developmental capacity.

We studied the impact of age and the serum anti-Müllerian hormone (AMH)/follicle-stimulating hormone (FSH) levels on the number of cumulus–oocyte complexes (COCs) retrieved from female reciprocal and Robertsonian translocation carriers after controlled ovarian hyperstimulation (COH). The number of COCs retrieved after COH was retrospectively analyzed in female translocation carriers and 46,XX partners of male translocation carriers from 100 couples. The median number of COCs varied from nine to 16 and did not differ among subgroups of women categorized by age, presence and type of a translocation. The number of COCs correlated negatively with the woman’s age in both the reciprocal and the Robertsonian translocation carriers, while in 46,XX women no correlation was detected. The number of COCs did not differ between the reciprocal and the Robertsonian translocation carriers aged either <35 or ≥35 years. In translocation carriers, the number of COCs correlated with the serum AMH level only in the younger-age subgroups; the correlation was strong positive in reciprocal and moderate positive in Robertsonian translocation carriers. The 46,XX women aged both <35 and ≥35 years showed similar moderate positive correlations. Across all subgroups, the number of COCs correlated moderately negatively with the serum FSH level only in Robertsonian translocation carriers aged <35 years. Our results suggest that chromosomal translocations per se do not increase the risk of poor oocyte retrieval outcome after COH. In translocation carriers, oocyte retrieval outcome depends to a large extent on their age. The serum AMH level strongly predicts oocyte retrieval outcomes only in young reciprocal translocation carriers, while the serum FSH level has a moderate predictive value in young Robertsonian translocation carriers.

Background: Incorrect epigenetic modifications of the human genome may result in epigenetic disorders, thus, highlighting the necessity of studying chromosome epigenetic patterns in human development. Aim of the study: A comparative analysis of acetylated histone H3K9 (AcH3K9) patterns in human metaphase chromosomes from the lymphocytes of adults and fetuses. Materials and methods: The immunocytochemical detection of AcH3K9 in the metaphase chromosomes from PHA-stimulated peripheral lymphocytes of 13 adults and cord blood lymphocytes of 10 fetuses at 20-22 weeks of gestation. Results: Both in the chromosomes of the adults and the fetuses, AcH3K9 accumulated in the R- and T-, but not G-bands and avoided the regions of pericentromeric heterochromatin of the chromosomes 1, 9 and 16. When comparing the adult and the fetal chromosomes, different levels of AcH3K9 were revealed in a few bands: 2q31, 5p13, 5p15 and 16p13 had higher level of Н3К9 acetylation in adults, in contrast to 9q13 which was hyperacetylated in fetuses. Conclusion: The АсН3К9 distribution in metaphase chromosomes is band-specific and is similar between the adults and the fetuses, excluding a few bands with different acetylation levels.

BACKGROUND: It is common a wide range of reproductive disorders in couples with structural chromosome aberration in one of the partners, such as infertility, miscarriage, unsuccessful assisted reproductive technologies attempts. In this regard, predicting the reproductive outcome in a particular couple is an extremely difficult task. To solve it, it is necessary to consider the influence of many factors, including the type of chromosome translocation and the carriers sex. AIM: To evaluate the structure of reproductive disorders in couples where one of the partners was a chromosome translocation carrier, depending on its type: Robertsonian or reciprocal, and carriers sex. MATERIALS AND METHODS: In this retrospective cohort study, we analyzed the clinical and anamnestic data of 100 couples where one of the partners was a chromosome translocation carrier. Couples applied to fertility centers between March 2009 and May 2019. To assess the effect of the type of chromosomal translocation and carriers sex, we provided intergroup comparisons. RESULTS: Comparative analysis of somatic pathology and chronic gynecological diseases didnt reveal significant differences between groups of female patients (Fischers exact test, p 0,05). An intergroup comparison of reproductive outcomes in couples divided by the type of chromosome translocation: reciprocal or Robertsonian, and the carriers sex, detected significant differences. Primary infertility was significantly more often detected in couples with a male translocation carrier, secondary with a female carrier (Fishers exact test, p = 0,01). Pregnancy significantly more frequent occurred and, it was also significantly more often spontaneously interrupted in couples with a female carrying of reciprocal or Robertson translocation (2 = 13,29, df = 3, p = 0,004). Thus, a female carrying a chromosomal translocation is characterized by a greater risk of miscarriage. CONCLUSIONS: The chromosome translocation type and the carriers sex have a differential effect on the nature of reproductive disorders. Female carrying a chromosomal translocation increases the likelihood of both pregnancy and its spontaneous termination. In contrast, in couples with a male translocation carrier, the probability of both pregnancy and miscarriage is lower. Thus, the type of translocation and the carriers sex determine the individual risks of reproductive disorders, including infertility and miscarriage, which should be considered in the planning, choosing the method of onset and management of pregnancy.