Early planned birth and AEDC scores

A new University of Sydney study looked at the role of pregnancy length and type of delivery with later child development.

Research summary

What is the research about?

Fetal brain development rapidly increases after 32 weeks of pregnancy. Optimal time of birth is 39 to 40 weeks’ gestation. But earlier birth through cesarean delivery and labor induction is now more common. The clinical view is that birth just before the optimal date carries little risk.

If poorer developmental outcomes can occur from early planned birth, and waiting is possible, then there is a need to inform clinicians and families.

What did the researchers do?

The study linked data from all live births between 2002 and 2007 in New South Wales, Australia to children’s later scores on the Australian Early Development Census in 2009 or 2012.

The researchers looked at:

  • Type of birth
    • Vaginal birth or caesarean delivery
  • Onset of labour
    • Spontaneous, induced, or prelabour caesarean delivery
  • Child development
    • Developmentally high risk (Vulnerable on two or more AEDC domains)

What did the researchers find?

The proportion of children developmentally high risk dropped with increasing length of pregnancy.

  • 13.1% of pre-term births (less than 37 weeks)
  • 10.2% of early-term births (37-38 weeks)
  • 9.0% of term births (39-40 weeks)

After controlling for confounders, caesarean and induced delivery were associated with greater risk for worse child development than spontaneous vaginal delivery.

  • Labour induction +6%-18% risk
  • Prelabour caesarean delivery +5%-12% risk
  • Caesarean delivery after induction +14%-18% risk

What does the research mean?

The risk of poor development increases for every additional week a child is born before 39-40 weeks’ gestation. This risk increases more for caesarean or induced delivery. Because the timing of a planned birth can change, it may help to delay birth if safe to do so.

The study supports clinical recommendations limiting labor induction or prelabour cesarean delivery for nonmedical reasons before 39 to 40 weeks’ gestation.