How many missed abortions are caused by embryonic chromosomal abnormalities and what are their risk factors?

Abstract

Introduction: Though embryonic chromosome abnormalities have been reported to be the most common cause of missed abortions, previous studies have mainly focused on embryonic chromosome abnormalities of missed abortions, with very few studies reporting that of non-missed abortion. Without chromosome studies of normal abortion samples, it is impossible to determine the risk factors of embryo chromosome abnormalities and missed abortion. This study aimed to investigate the maternal and embryonic chromosome characteristics of missed and non-missed abortion, to clarify the questions that how many missed abortions are caused by embryonic chromosomal abnormalities and what are their risk factors.Material and methods: This study was conducted on 131 women with missed or non-missed abortion from the Longitudinal Missed Abortion Study (LoMAS). Logistic regression analysis was used to identify the association between maternal covariates and embryonic chromosomal abnormalities and missed abortions. Data on the characteristics of women with abortions were collected.Results: The embryonic chromosome abnormality rate was only 3.9% in non-missed abortion embryos, while it was 64.8% in missed-abortion embryos. Assisted reproductive technology and prior missed abortions increased the risk of embryonic chromosome abnormalities by 1.637 (95% CI: 1.573, 4.346. p = 0.010) and 3.111 (95% CI: 1.809, 7.439. (p < 0.001) times, respectively. In addition, as the age increased by 1 year, the risk of embryonic chromosome abnormality increased by 14.4% (OR: 1.144, 95% CI: 1.030, 1.272. p = 0.012). Moreover, advanced age may lead to different distributions of chromosomal abnormality types.Conclusion: Nearly two-thirds of missed abortions are caused by embryonic chromosomal abnormalities. Moreover, advanced age, assisted reproductive technology, and prior missed abortions increase the risk of embryonic chromosomal abnormalities.

Evaluating the link between chromosomal abnormalities and diminished ovarian reserve, mode of conception, and history of prior miscarriages in cases of early missed abortion using CNV-seq

“…Over 50% of MAs result from chromosomal abnormalities, with previous estimating anywhere from 50-70% of MAs to be associated with these abnormalities [9][10][11] . Variations in these rates may be the result of gestational age, the detection techniques employed, and other variables.…”

“…In total, this study included 1490 cases, with a mean age of 31.07 ± 4.9 years (18-49 years), a mean gravidity of 2.29±1.43 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11), and a mean parity of 0.35±0.62 (0-4). For details regarding the clinical characteristics of these patients, see Table 1.…”

“…These abnormalities entail the absence or presence of particular chromosomes owing to errors that arise during the rst round of meiotic division giving rise to an egg cell [13] . Autosomal trisomy is the most common nding in cases of early MA, with trisomies 13, 16, 18, 21, and 22 being particularly frequent [14] , followed by X monosomy and polyploidy [9,10] . For instance, one prior survey of 1,030 products of conception from MAs following single-embryo transfer detected aneuploidy in 80.6% of cases, of which 62.3% were trisomies, 7.8% were double trisomies, 0.5% were triploid or tetraploid, 1.3% exhibited 21-monosomy, 3.2% exhibited X-monosomy, 0.1% exhibited 47,XXY, 1.0% exhibited polyploidy, 1.0% presented with mixed abnormalities, 1.1% exhibited embryonic chimerism, and 2.4% exhibited structural abnormalities [15] .…”

“…Some studies, however, have argued that ART can contribute to a greater risk of embryo chromosomal abnormalities and miscarriage [37] . While the general types of chromosomal abnormalities in cases of ART may be similar to those for natural conception [9] , particular ART techniques also have the potential to preferentially give rise to certain abnormalities. ICSI, for instance, is linked to a greater risk of non-disjunction abnormalities, higher X monosomy rates [38] , and lower polyploidy rates [39] .…”

“…These trends remained intact when strati ed according to age, supporting a link between ART and changes in the incidence of trisomies. ART has been reported to increase the risk of chromosomal numerical abnormalities, particularly in cases of trisomies [9] . One limitation of these analyses is that no effort was made to distinguish between different ART protocols when assessing chromosomal abnormality rates, underscoring a need for further studies aimed at clarifying the relationships between ART and these outcomes in order to guide the development of more optimal ART strategies.…”