Preterm Birth in America (2025)
About one in eight U.S. babies is born early. The risk is highest for the youngest and oldest mothers, and for twins and triplets.
Key findings
- About one in eight U.S. births came early in 2025: 12.1% were preterm, delivered before 37 completed weeks of gestation (438,570 babies).
- The risk is U-shaped by age: highest for the youngest and oldest mothers (14.2% under 20 and 17.5% at 40 and older) and lowest in the late 20s and early 30s.
- Multiples are the strongest driver: 10.7% of single births were preterm, versus 57.9% of twins and 95.0% of triplets.
- Because preterm birth is the leading driver of infant illness, these gaps map closely onto which babies need intensive care.
A birth before 37 weeks is the single biggest risk factor for newborn complications. This measures the preterm rate for every 2025 U.S. birth and how it varies by the mother's age and by whether she carried one baby or more. These are exact counts from the near-census of birth records.
Preterm birth, 2025
Preterm rate by mother's age
| Category | Preterm rate |
|---|---|
| Under 20 | 14.2% |
| 20 to 24 | 11.7% |
| 25 to 29 | 11.1% |
| 30 to 34 | 11.5% |
| 35 to 39 | 13.4% |
| 40 and older | 17.5% |
By plurality
| Plurality | Preterm rate | Births |
|---|---|---|
| Single | 10.7% | 3,506,908 |
| Twin | 57.9% | 107,493 |
| Triplet | 95.0% | 2,254 |
Preterm is a gestational age under 37 completed weeks (NCHS combined gestation). Exact counts; no sampling margins of error.
Data Sources & Methodology
The figures on this page are computed directly from the source data below. Narrative text accompanies the figures but never generates them.
CDC/NCHS Natality (Births) Public Use File
- Vintage:
- 2025
- Access:
- BigQuery
- Cadence:
- annual
A near-census of U.S. births for the year, drawn from birth certificates. Each row is one birth, carrying the age, education, race and Hispanic origin, and marital status of the mother; prenatal care, pre-pregnancy BMI, and smoking; the delivery method, attendant, birth place, and payer; and the sex, birth weight, gestational age, plurality, and Apgar score of the infant. It supports analysis of who is being born and how, by maternal characteristics.
Every U.S. birth is registered on a birth certificate, which NCHS compiles into an annual public-use micro-file. Each record describes one birth and its mother.
The file covers essentially all registered births in the data year, not a probability sample. Statistics are exact counts; there are no sampling weights and no sampling margins of error.
To protect confidentiality, the public-use file omits state and county. Analyses here are national and by maternal and infant characteristics; state-level figures require CDC WONDER or the restricted-use file.
Gestational age uses the obstetric estimate (combined gestation); birth weight is in grams; delivery method distinguishes vaginal from cesarean; some reported items (education, payer, smoking) carry reporting flags for areas that had not adopted the 2003 certificate revision.
- No state or county geography in the public-use file.
- A few items (for example payer and smoking) were not reported by every area in early revision years; reporting flags identify coverage.
- The final annual file lags roughly a year; provisional counts via CDC WONDER are more timely but less detailed.
- Birth-certificate data depend on accurate completion by hospitals and reporting areas.
How these figures were produced
- Estimate type:
- Administrative near-census (exact counts)
- Weighting:
- None (not a weighted sample)
Suggested citation
Centers for Disease Control and Prevention, National Center for Health Statistics, 2025 Natality Public Use File. Analysis by Matt George, itsmattgeorge.com. Retrieved 2026-10-24.