After analyzing the birth history of over 400,000 schoolchildren, Scottish researchers found that the risk of autism and/or special educational needs (SEN) were 1.16 times greater for babies born at 37 to 39 weeks of gestation, compared to those born at the full 40 weeks. This finding has important implications for the timing of elective Cesarean deliveries.

Children with SEN (special educational needs) may have either:

  • A learning difficulty, such as dyslexia or autism that requires special educational help.
  • A physical difficulty, such as poor vision or deafness that requires special educational help.

The researchers, led by Jill Pell, Section of Public Health, University of Glasgow, Glasgow, United Kingdom explained that we already knew that a baby born, say at 24 weeks, has a higher risk of SEN later in life compared to a full term baby (40 weeks of gestation).

However, the risks of SEN later in life for babies born across a whole range of gestation (from 24-40 weeks) had not previously been investigated.

Pell and team’s study showed that compared to babies born at 40 weeks, those born at 37-39 weeks of gestation were 1.16 times as likely to have an SEN. Although the risk of SEN was much higher in preterm than in early term babies, because many more children were born between 37 and 39 weeks (about a third of babies) than before 37 weeks (one in 20 babies), early term births accounted for 5.5% of cases of SEN whereas preterm deliveries accounted for only 3.6% of cases.

The researchers explained that the these results demonstrate that even a baby born at 39 weeks has a higher risk of SEN, compared to babies born a week later. The normal timing for elective deliveries (e.g. cesarean section) is 39 weeks.

“Gestational Age at Delivery and Special Educational Need: Retrospective Cohort Study of 407,503 Schoolchildren.”
MacKay DF, Smith GCS, Dobbie R, Pell JP (2010)
PLoS Med 7(6): e1000289

Written by Christian Nordqvist