London, Jul 9 (IANS): A study suggests that pregnant girls aged between 14 and 17 years are at higher risk of giving birth to premature babies, especially if it is a second child.

Researchers demonstrate this association and call for better health education and the promotion of contraception after a teenager has given birth for the first time.

Ali Khashan, University College Cork, Ireland, worked with a team of researchers and studied women aged between 14-29 who had a live baby in the north west of England between January 2004 and December 2006.

The researchers identified 3,636 people between the age of 14 and 17 at the time of birth, 7,506 aged between 18 and 19 and 45,211 aged between 20 to 29.

The rates of teenage pregnancy increased with increasing social deprivation as more than a third of the teen mothers came from the most socially deprived areas.

Teenage mothers were more likely to be underweight and of white ethnic background, reported open access journal BMC Pregnancy and Childbirth.

Women who gave birth during the teenage years were at increased risk of preterm (premature) and very preterm delivery, said a university statement.

This risk was higher for younger teenager mothers than for older teenagers and the risk was greater in second pregnancies than in first in the 14-17 group.

"It is possible that the increased risk of poor pregnancy outcome is related to biological immaturity," said Khashan.