Introduction
Recurrent miscarriage (RM) is defined by the ESHRE guidelines in November 2017 as the loss of two or more pregnancies[1]. According to the history of live birth, it can be divided into primary and secondary recurrent miscarriage[2]. The causes of recurrent miscarriage are very complicated. In addition to anatomy, endocrine, thrombophilic, immune and other factors,embryo chromosomal abnormalities are often considered an important cause of miscarriage[3, 4]. The embryo chromosomal abnormality rate in the general population is 60%[5], while the rate in the recurrent miscarriage is 29%-60%[6-8]. Embryonic chromosomal abnormalities may occur during the mitosis of embryo development, or come from parental abnormal ovum or sperm. For example, parental balanced chromosomes lead to unbalanced gametes which might cause abortion [9]. Therefore, the chromosomal karyotype of both parents is considered to be an important examination in the cause of recurrent miscarriage recommended by American Colleges of Obstetricians and Gynecologists[10]. However, the evidence that parental chromosomal abnormalities lead to miscarriage is still unclear, a considerable percentage of couples with chromosomal abnormalities have successfully given birth[11]. In addition to chromosomal factors, other factors may cause miscarriages that coexist with chromosomal aberrations. Due to the limited number of samples in couples with abnormal chromosomes, other known and unknown pathological factors were studied as homogeneous, and chromosome aberrations could hardly completely solely studied with removal of other pathological factors. Therefore, it is more difficult to judge and analyze the cause of miscarriage due to parental chromosomal abnormalities, which often makes clinicians’ understanding of parental chromosomal abnormalities leading to miscarriage not accurate enough.
5680 couples with recurrent miscarriage were diagnosed in our reproductive center from 2008 to 2018. The study attempts to summarize the frequency of abnormal chromosomal karyotype couples, the topography of abnormal types, and the frequency of the male and female carriers in the recurrent miscarriage population. The coexistence of other causes of miscarriage and respective pregnancy outcomes were further evaluated. We hope that the results of the study will provide more scientific evidences for genetic counseling among RM couples.