TOPLINE:

In a retrospective cohort study, a combination of four abnormal ultrasound features —gestational sac mean diameter (GSMD) < fifth centile, yolk sac mean diameter (YSMD) ≥ 95th centile, crown-rump length (CRL) < fifth centile, and bradycardia during early pregnancy — predicted chromosomal abnormalities with a specificity of 100%.

METHODOLOGY:

• Researchers conducted a retrospective observational cohort study analysing 158 women diagnosed with a miscarriage during the first trimester (median gestational age, 67 days) who underwent successful cytogenetic testing of pregnancy tissue at University College London Hospital between January 2017 and February 2024.
• Overall, 136 women received routine testing due to a history of recurrent miscarriage and 22 self-funded the cytogenetic testing. A total of 46 women had a normal and 112 had an abnormal karyotype, with a median maternal age at conception being significantly higher in the abnormal vs normal karyotype group (38 vs 35 years; P = .0005).
• Outcomes included associations of GSMD, YSMD, CRL, embryonic heart rate, and the presence of an amniotic sac with cytogenetic findings.

TAKEAWAY:

• Pregnancies with abnormal karyotypes had significantly lower median GSMD centiles (P = .005) and CRL centiles (P = .003) than those with normal karyotypes. An abnormal karyotype was also linked to a smaller gestational sac (odds ratio [OR], 0.98; P = .03) and CRL below the fifth centile (OR, 5.51; P < .001) across all gestational ages.
• Bradycardia and enlarged YSMD (≥ 95th centile) occurred more frequently in pregnancies with abnormal karyotypes (P = .04 and P = .03, respectively). An increase in YSMD was significantly associated with abnormal karyotypes across all gestational ages (OR, 1.02; P = .03).
• The tetrad of aneuploidy (GSMD < fifth centile + YSMD ≥ 95th centile + CRL < fifth centile + bradycardia) was significantly associated with abnormal karyotypes, specifically in cases examined at 10 weeks or before (OR, 7.51; P < .001), and demonstrated a specificity of 100% (95% CI, 92.29%-100%) for abnormal karyotypes.

IN PRACTICE:

"[The study] results suggest a role for ultrasound in providing diagnostic insights beyond viability assessment, aiding in the counseling and management of patients at risk of early pregnancy complications," the authors wrote.

SOURCE:

This study was led by T. Setty, University College London, EGA Institute for Women's Health, London, England. It was published online on January 03, 2026, in Ultrasound in Obstetrics & Gynecology.

LIMITATIONS:

The retrospective design and selection bias in the study, the relatively small sample size, and the significant proportion of culture failures limited the scope of the study. The routine karyotyping remained unavailable for most single sporadic losses during the first trimester, which may have left the cause of miscarriage unexplained and compounded psychological distress.

DISCLOSURES:

No funding information was provided for this study. One author reported receiving speaker fees from GE HealthCare and Samsung.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.