Twin Birth Rates by Country: Official Data and Comparisons

The short answer

There is no honest single “current ranking” of twin birth rates by country. Official sources do not always count the same event, cover the same year or treat stillbirths in the same way.

For a comparable longitudinal view, use the Twin Birth Data Atlas. It contains 2,617 selected country-year observations for 25 countries and territories from the Human Multiple Births Database (HMBD), plus downloadable CSV files and a documented selection method.

Three rates that sound similar but are not interchangeable

Twin deliveries per 1,000 deliveries

This is the HMBD measure used in our Atlas. One delivery of two babies counts as one twin delivery. A rate of 15 therefore means that 15 out of 1,000 deliveries were twin deliveries.

Twin babies per 1,000 births

The US National Center for Health Statistics uses a birth-level rate. Each twin baby is counted among all babies born. Its value is consequently about twice a delivery-level twinning rate, before accounting for differences in coverage.

The CDC’s June 2026 report gives a US twin birth rate of 30.1 twin babies per 1,000 total births in 2024, down 11% from 33.9 in 2014.

Multiple maternities per 1,000 maternities

The UK Office for National Statistics reports maternities resulting in twins, triplets or higher-order multiples. The ONS 2024 bulletin reports 13.8 multiple maternities per 1,000 maternities in England and Wales, down from 14.4 in 2023.

Because this category includes more than twins, it is not identical to the HMBD twinning rate.

What the HMBD makes comparable

The Human Multiple Births Database compiles national vital-statistics series and defines its twinning rate as twin deliveries divided by all deliveries, multiplied by 1,000. The release used by TwinCalc is dated 26 May 2025.

Our Atlas keeps that definition throughout. When a country-year has several candidate records, the processing rule prefers records including stillbirths, followed by records excluding stillbirths, mixed coverage and unknown coverage. Ties use the largest delivery denominator. The selected source code and number of candidates remain visible in the full CSV.

How to compare countries responsibly

Before comparing two figures, check four things:

1. Denominator: deliveries, individual babies, pregnancies or maternities.
2. Reference year: the latest available year differs by country.
3. Coverage: live births only or births including stillbirths.
4. Source revision: national series may be corrected after publication.

The Atlas table is alphabetical rather than a league table because its latest observations range from 1996 to 2023. Sorting those values as if they described the same moment would create a false ranking.

Why rates can change

Population-level changes may coincide with maternal-age patterns, assisted reproduction, embryo-transfer practices, registration changes and other country-specific factors. A descriptive time series cannot show which factor caused a rise or fall on its own.

This distinction matters for personal decisions too. A national rate is context, not an individual forecast. The educational twin-probability overview uses a risk-factor model and clearly separates that model from the observed population data.

Sources and reusable data

• Explore the interactive Twin Birth Data Atlas
• Download the complete derived annual CSV
• Read the HMBD methodology
• Read the HMBD citation and CC BY 4.0 terms

The database is credited to the Human Multiple Births Database and distributed by INED. TwinCalc’s selection and presentation are derived work, documented separately from the source.