Conception rates in under-18s

Rates of teenage pregnancy are often associated with poor educational achievement, poor physical and mental health, social isolation and poverty. The Public Health Outcomes Framework for England includes under-18 conceptions as a key measure for health inequalities and child poverty.

How have conception rates changed over time?

The rate of conception in under-18s has been decreasing over time from 47.7 per 1,000 population in 1990, to 22.9 per 1,000 population in 2014 – this is a decrease of 52%. The rate of decline seems to have accelerated since 2007. In 1999, the Teenage Pregnancy Strategy was launched, which included a target to halve the under-18 conception rate between 1998 and 2010. Although progress in reducing the under-18 conception rate was made, we can see that the target of 23.3 per 1,000 population was missed by over ten conceptions per 1,000 population. Despite the end of this strategy in 2010, the conception rate continued to fall in 2014.

Despite this positive trend, when compared to other countries, UK still has one of the highest birth rates to women aged 15-17, while Denmark, Slovenia, the Netherlands and Sweden the lowest (see ONS Comparison of teenage pregnancy).

About this data

Under-18 conception rate per 1,000 population:

  • Numerator: total conceptions in all women aged under 18
  • Denominator: total female population aged 15 to 17.

Office for National Statistics (ONS) conception statistics are compiled by combining information from birth registrations and abortion notifications. Conception statistics include pregnancies that result in:

  • one or more live or still births
  • a legal abortion under the Abortion Act 1967.

Miscarriages and illegal abortions are not included. The date of conception is estimated using recorded gestation for abortions and stillbirths, and assuming 38 weeks gestation for live births. A woman’s age at conception is calculated as the number of complete years between her date of birth and the date she conceived.

The postcode of the woman’s address at time of birth or abortion is used to determine local authority/ward of residence at time of conception.

Only about 5% of under-18 conceptions are to girls aged 14 or under and to include younger age groups in the base population would produce misleading results. The 15 to 17 age group is effectively treated as the 'population at risk'.

ONS changed the methodology for estimating age at conception in 1997. Rates for 1987 to 1996 were revised to provide a comparable time series from 1987 onwards. 


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