Girls' disrupted childhoods predict earlier pregnancy

15 November 2010

Newly-published research from the National Child Development Study shows that girls are more likely to become pregnant at an early age if they were not breast-fed, moved house frequently, or had a father who was absent or uninvolved in parenting.

A team of researchers from Newcastle University have used data from the National Child Development Study to examine which factors in childhood predict early pregnancy.

The researchers looked at four kinds of disruption that might affect the family lives of young girls and found that each one brought forward the age at which they first became pregnant by six months on average.

The study found that even after controlling for major differences such as the parents' income and social class, four factors during upbringing had an impact on the age at which a woman had her first child: whether she was breastfed; how involved her parents were in her upbringing; whether her father was present; and whether her parents moved house regularly.

Daniel Nettle, one of the authors, said the key message is that what happens early in life is hugely influential. "As a society, we should never forget that. If you get girls when they're 14 or 15 and say, 'Hey girls don't have babies young', it may not do a lot at that point if there've been more influential events much earlier that set them on a path towards a desire to have short time horizons and have babies younger.  A lot of those things are to do with stress and wellbeing of kids in deprived areas."

"Rather than just telling girls to use condoms," he added, "authorities should think much more about the context of people's early years."

The results showed low paternal involvement in the first seven years meant an average reduction in the age of first pregnancy of 0.74 years; prolonged separation from a mother in childhood entailed a 0.64-year reduction. And the effects could be added together, so if a girl had two of the disruptions, her age at first pregnancy was around a year earlier than average. Having all four disruptions brought forward the age by around two years.

Nettle acknowledged it was hard to be absolutely sure that the early life factors were responsible for the age shift, but he was confident his research had controlled statistically for other factors such as income and education.

The findings support and extend earlier work on the 1946 cohort (National Survey of Health and Development) published in 1983 by Kath Kiernan and Ian Diamond in Population Studies.

NETTLE, D., COALL, D.A. and DICKENS, T.E.  Early-life conditions and age at first pregnancy in British women. Proceedings of The Royal Society B, advance online access, 10 November 2010