Objective To investigate the correlation between chromosome karyotype of villus cells and causes of abortion in spontaneous abortion patients.

Methods From January 2023 to April 2025, women diagnosed with embryonic or fetal arrest in the gynecology department were selected as the study objects. Uterine clearance was performed for missed abortion patients who failed to completely discharge the embryonic tissue by medical drainage to obtain the abortion tissue. Primary cell culture was used to isolate adherent cells, and metaphase cells were harvested for chromosome preparation and karyotype analysis. The correlations between the age, gestational week, number of abortions, mode of pregnancy, fetal sex and chromosome karyotype abnormality of the pregnant women with missed abortion was compared. If the villi sample with chromosome structure abnormality was detected, the chromosome karyotype of the peripheral blood of the parents was further detected.

Results Among 195 cases of missed abortion, 180 cases of chorionic villus specimens were successfully cultured, with a success rate of 92.31%. A total of 88 cases of chromosomal abnormal karyotypes were detected, with an abnormal karyotype rate of 48.89%. Among them, there were 83 cases (94.32%) of chromosomal number abnormalities and 5 cases (5.68%) of chromosomal structure abnormalities. The abnormal karyotype rate of miscarriage of chorionic villi in women aged ≥35 years was 63.41%, which was higher than the abnormal rate of 44.60% in women aged ＜ 35 years (P ＜ 0.05). The abnormal karyotype rate of miscarriage villi in women with a gestational age of ≤12 weeks was 58.02%, which was higher than the abnormal rate of 24.49% in women with a gestational age of ＞ 12 weeks (P ＜ 0.01). There was no statistically significant difference in the abnormal rate of villus karyotype during miscarriage among women grouped by the number of miscarriages, pregnancy mode and embryo gender (P ＞ 0.05).

Conclusions Embryonic chromosome abnormality is a major cause of embryo termination and spontaneous abortion in pregnant women. Advanced maternal age (≥35 years old) and the first trimester of pregnancy (≤12 weeks) are high-risk factors for chromosomal karyotype abnormalities in chorionic villi during spontaneous abortion in pregnant women. Chromosomal karyotype analysis of chorionic villi from women with spontaneous abortion can provide valuable diagnostic and therapeutic guidance for future pregnancies.