Teenage girls living in deprived areas are four times more likely to fall pregnant than those living in more affluent areas, official data shows,
More under-16s are becoming pregnant
Office for National Statistics figures reveal 70.9 per 1,000 girls aged 15-17 in deprived areas conceive compared with 16.2 per 1,000 in richer areas.
The difference was even greater when just under-16s were considered, the figures for England and Wales show.
Experts warn action is needed where pregnancies are "stubbornly high".
The government wants to halve the conception rate in under-18s in England by 2010.
The ONS statistics also show fewer teenagers in deprived areas have abortions.
In the least deprived areas, 71% of pregnancies in under-18s end in abortion, compared with 39% in the most deprived.
Among girls under 16, the proportions were 77% and 50%.
The ONS figures also show that the overall conception rate in under 18s remained virtually stable from 42,198 in 2004 to 42,187 in 2005.
But there has been a 4% rise in the number of under-16s falling pregnant - increasing from 7,615 pregnancies in 2004 to 7,917 in 2005.
Gill Frances, chair of the Independent Advisory Group on Teenage Pregnancy, said: "We are really pleased with the excellent progress being made by more than 80% of local authorities, who are proving that teenage pregnancy can be reduced.
"That success needs to be driven forward nationwide."
But she attacked those primary care trusts which were making cuts to their contraceptive services, sometimes closing clinics.
"We are extremely concerned about the ongoing closure of community family planning services which prevent young people getting contraceptive help to prevent unplanned teenage pregnancy.
"This has partly been to offset financial deficits, but also because teenage pregnancy has not been considered a priority."
Anne Weyman, chief executive of the FPA (Family Planning Association), said: "Teenage pregnancy is a complex social issue requiring long-term strategic solutions.
"The dramatic reduction in teenage pregnancy in some parts of the country clearly demonstrates that the Teenage Pregnancy Strategy can make a tremendous difference.
"However, other areas in England still have stubbornly high teenage pregnancy."
Val Buxton, of Brook, the sexual health charity for young people, added: "As long as young people's need for better education and services is neglected, reducing rates of teenage pregnancy will be an uphill struggle."
Beverley Hughes, minister for children, young people and families, said she was pleased the figures show teenage pregnancy rates overall were continuing to fall.
But she said: "We know we cannot be complacent. There is still much we want to do and we have ambitious goals to reduce teenage pregnancy rates even further.
"The figures show a wide variation in performance across the country and this demonstrates how critical local delivery is. We know what works and have given guidance to local authorities and PCTs, setting out the key ingredients for a successful strategy."