The etiology of recurrent spontaneous abortion (RSA) is complex, with embryonic chromosomal abnormalities representing a major contributing factor. This study aims to characterize the embryonic chromosomal abnormalities products of conception (POC) from RSA patients, compare the composition of abnormalities across various etiological subtypes, and analyze the association between maternal clinical factors and different types of chromosomal abnormalities.

A retrospective cohort study was conducted with predefined inclusion and exclusion criteria, a unified etiological evaluation protocol, standardized copy number variation sequencing (CNV-seq) and abnormality interpretation criteria, and systematic clinical variable extraction and statistical analysis to ensure quality control. A total of 534 RSA patients involving 629 pregnancy events who underwent POC CNV-seq in our hospital between January 2021 and December 2024 were recruited. According to systematic etiological evaluation, the patients were classified into a maternal/parental factor-explained recurrent spontaneous abortion (MPF-eRSA) group and a maternal/parental factor-unexplained recurrent spontaneous abortion (MPF-uRSA) group. The distribution of embryonic chromosomal abnormalities was compared between the 2 groups. Mixed-effects logistic regression models were used to evaluate the associations of maternal age, gestational age, number of previous miscarriages, mode of conception, and maternal risk factors with different types of chromosomal abnormalities. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were further performed on genes covered by RSA-related pathogenic CNVs (PCNVs), and the selected candidate genes were preliminarily validated by qRT-PCR.

Among the 629 POC samples, chromosomal abnormalities were detected in 321 cases, with an overall detection rate of 51.0%. Numerical abnormalities were the predominant type, accounting for 75.1% of abnormal cases. Univariate analysis showed that the MPF-uRSA group had higher proportions of aneuploidy and single trisomy than the MPF-eRSA group (P<0.001), whereas mosaicism was more frequent in the MPF-eRSA group (P=0.015). Mixed-effects logistic regression analysis revealed a lower risk of overall chromosomal abnormalities in the MPFeRSA group than the MPF-uRSA group (OR=0.41, 95%CI: 0.21 to 0.82, P=0.011). Maternal age was positively associated with the risk of overall chromosomal abnormalities (OR=1.48, 95%CI: 1.22 to 1.80, P< 0.001), aneuploidy (OR=1.44, 95%CI: 1.17 to 1.77, P<0.001), and single trisomy (OR=1.55, 95%CI: 1.20 to 2.00, P<0.001). The risks of aneuploidy (OR=0.24, 95%CI: 0.11 to 0.51, P<0.001) and single trisomy (OR=0.14, 95%CI: 0.05 to 0.36, P<0.001) were significantly lower in the MPF-eRSA group than the MPF-uRSA group. Maternal endocrine factors were associated with an increased risk of single trisomy (OR=2.87, 95%CI: 1.19 to 6.90, P=0.018), while maternal genetic factors were associated with increased risks of single trisomy (OR=3.75, 95%CI: 1.20 to 11.69, P=0.023) and PCNVs (OR=9.91, 95%CI: 2.87 to 34.21, P< 0.001). GO/KEGG enrichment analyses showed that the genes covered by RSA-related PCNVs were mainly involved in DNA damage repair, extracellular matrix homeostasis, and inflammation-related processes. qRT-PCR showed that RAD21, LIG4, and COL4A1 were downregulated, whereas CTSB and GSDMD were upregulated in the RSA group compared with the control group(P<0.05).

Embryonic chromosomal abnormalities in POC from RSA patients are predominantly numerical abnormalities, and their distribution differs across etiological subtypes. Aneuploidy is more common in MPF-uRSA patients. Maternal age is an important influencing factor for embryonic chromosomal abnormalities, mainly associated with the risk of aneuploidy. POC genetic testing combined with etiological classification may help improve etiological evaluation, risk stratification, and clinical management of RSA.

Preterm birth is the leading cause of neonatal morbidity and mortality. Conventional two-dimensional (2D) ultrasound measurement of cervical length (CL) has limitations in predicting spontaneous preterm birth (SPTB), making it difficult to accurately identify some high-risk pregnant women at early stages. This study aims to investigate the value of three-dimensional (3D) ultrasound measurement of cervical volume (CV) in predicting SPTB, providing a new direction for SPTB prediction.

A nested case-control trial was conducted on the pregnant women undergoing prenatal examinations in our department from January 2024 to November 2025. Transvaginal 2D ultrasound measurement of CL and 3D ultrasound measurement of CV were performed at 12 to 24 weeks and 28 to 32 weeks of gestation, respectively. After applying our inclusion and exclusion criteria, 237 cases with complete follow-up and medical records were included as study subjects. According to gestational age at delivery, the participants were divided into an SPTB group (n=36) for deliveries at 28 to <37 weeks, and a full-term delivery (FTD) group (n=201) for deliveries at ≥37 weeks. Univariate analysis was initially performed to compare various indicators between the 2 groups. To ensure model stability, 1∶1 propensity score matching (PSM) was employed for age, gestational weight gain, gravidity, parity, history of preterm birth, history of cervical conization, history of full-term delivery, and premature rupture of membranes. Univariate and multivariate conditional logistic regression analyses were applied to the PSM-matched SPTB (n=27) and FTD (n=27) groups to assess the independent predictive value of CL and CV for SPTB. ROC curves were plotted to evaluate the predictive efficacy of CL and CV for SPTB, calculating AUC values, optimal cutoff values, sensitivities, and specificities. Pearson correlation analysis was conducted to assess the association between CL and CV.

① Intergroup analysis showed statistically significant differences between the SPTB and FTD groups in terms of age, gestational weight gain, gravidity, parity, history of cervical conization, history of fullterm delivery, and premature rupture of membranes (P<0.05). ② After PSM, no significant differences were found between the SPTB and FTD groups in these above factors. ③ At 12 to 24 weeks of gestation after matching, CL was slightly lower in the SPTB group than in the FTD group, but the difference was not statistically significant (31.90±5.96 mm vs 33.70±6.97 mm, P=0.314); the CV in the SPTB group was significantly smaller than that in the FTD group (28.45±5.67 cm³ vs 32.72±6.23 cm³, P=0.011). At 28 to 32 weeks of gestation, the SPTB group exhibited both a significantly shorter CL (23.69±9.47 mm vs 30.58±8.48 mm, P=0.007) and a significantly smaller CV (22.70±7.64 cm³ vs 28.91±8.09 cm³, P=0.005) compared to the FTD group. ④ In the univariate model at 12 to 24 weeks of gestation, CV was significantly associated with the risk of preterm birth (OR=0.768, 95%CI: 0.612 to 0.964, P=0.023). When both CL and CV were included in the multivariate model, CV remained statistically significant (OR=0.769, 95%CI: 0.611 to 0.967, P=0.025), with smaller CV indicating greater preterm birth risk. The AUC value of CV was 0.680 (95%CI: 0.537 to 0.824, P=0.023), with an optimal cutoff value of 32.47 cm³, a sensitivity of 81.5% and a specificity of 51.9%. In the univariate model at 28 to 32 weeks of gestation, both CL (OR=0.864, 95%CI: 0.771 to 0.968, P=0.011) and CV (OR=0.827, 95%CI: 0.688 to 0.994, P=0.043) were significantly associated with the risk of preterm birth. When both were included in the multivariate model, neither showed statistical significance (P>0.05). Pearson correlation analysis revealed a strong positive correlation between CL and CV (r=0.689, P<0.001). The AUC value of CL was 0.717 (95%CI: 0.580 to 0.855, P=0.006), with an optimal cutoff value of 31.5 mm, a sensitivity of 81.5% and a specificity of 63%. The AUC value for CV was 0.706 (95%CI: 0.567 to 0.846, P=0.009), with an optimal cutoff value of 26.7 cm³, a sensitivity of 77.8% and a specificity of 63%. ⑤ CL was significantly shorter at 28 to 32 weeks of gestation compared to that at 12 to 24 weeks (27.13±9.56 vs 32.80±6.49 mm, P<0.001), and CV was obviously smaller (25.80±8.40 vs 30.58±6.28 cm³, P<0.001).

3D ultrasound measurement of CV at 12 to 24 weeks of gestation may have value in early identification of high-risk pregnant women for preterm birth.