Babies who are smaller than expected at birth tend to score lower on school tests as teenagers, according to a study led by the University of Warwick and reported by Yahoo.
The research tracked more than 92,000 children from infancy through adolescence. All of the children in the study were born at full term, meaning between 37 and 41 weeks of pregnancy.
The findings were published in the American Journal of Obstetrics and Gynecology. The work was carried out with the PsychGen Centre at the Norwegian Institute of Public Health and other institutions in Norway.
Why it matters
The study suggests that growth in the womb can leave a mark on learning that lasts well past early childhood. Researchers found that children who weighed less than most babies of the same sex born at the same stage of pregnancy generally earned lower marks in subjects such as mathematics and reading.
Those gaps were still visible in adolescence, according to the reporting. That indicates the connection between birth size and academic results carries into the mid-teens rather than fading once children start school.
Prof Dieter Wolke said that for babies delivered at term, being small for their stage of pregnancy may point to effects on the brain that influence learning and continue into the teenage years.
He added, however, that the long-term consequences of being born small could be shaped by stimulation in the home and support at school.
What the researchers examined
The team compared children against others of the same sex born at the same point in pregnancy, rather than applying one weight standard to every baby. The analysis drew on national school tests in maths, reading and English, including assessments taken at roughly 10 to 11, 13 to 14 and 14 to 15 years of age.
A separate part of the study looked at children born at 37 to 38 weeks. Those children tended to show slightly weaker language and movement skills in early childhood than children born later in pregnancy, but the differences had largely disappeared by the time they began school.
The researchers assessed language and motor skills at about six months, 18 months, three years and five years of age.
Prof Siobhan Quenby said not every baby born smaller than expected would go on to have difficulties. Even so, she said the results highlighted the value of tracking a baby's growth and making sure children get suitable support as they grow.
She also said the study was significant because it showed that babies of normal size, or large for their stage of pregnancy, face no long-term effects from arriving a few weeks before their due date.
The findings add to a body of work on how conditions before birth relate to later development, and they point to the school years as a period when children born small may benefit from closer attention. What to watch: whether future research identifies which forms of home and classroom support do most to narrow the gaps the study observed.
