Trisomy 18

Rare, genetic, and present at birth, Children and teens. Also called: Edwards syndrome.

How common is Trisomy 18 in the US?

Birth prevalence of trisomy 18, 3.2 cases per 10,000 live births (95% CI 3.0–3.3): 3.2 (Live births in 11 population-based U.S. birth-defects surveillance programs that ascertained all pregnancy outcomes and used medical-record abstraction; pooled surveillance covered 4,231,701 live births (about 23% of U.S. births); United States surveillance programs contributing to the 2018–2022 national-estimates analysis, 2018-2022). Source: Centers for Disease Control and Prevention / National Birth Defects Prevention Network, 2026. Label: VERIFIED.

• 3.2 Birth prevalence of trisomy 18, 3.2 cases per 10,000 live births (95% CI 3.0–3.3). Out of: Live births in 11 population-based U.S. birth-defects surveillance programs that ascertained all pregnancy outcomes and used medical-record abstraction; pooled surveillance covered 4,231,701 live births (about 23% of U.S. births). Where: United States surveillance programs contributing to the 2018–2022 national-estimates analysis. When: 2018-2022. Label: VERIFIED.

  Trisomy 18 — 3.2

  Source: Prevalence of Selected Birth Defects from Population-Based Birth Defects Surveillance Programs in the United States, 2018–2022 Centers for Disease Control and Prevention / National Birth Defects Prevention Network, 2026.

Each figure measures something different. Do not compare them with each other or with other conditions.

Medical codes

• ICD-10-CM FY2026: Q91.3 Trisomy 18, unspecified (narrower). Other codes in this category also apply.

Research activity

As of 2026-09-24: 32 registered studies on ClinicalTrials.gov (search Trisomy 18) and 475 PubMed records, 2021 to 2025. A count of records is not how common or serious the condition is.

Population information, not medical advice. Methodology · Known limitations