The researchers from Durham and Lancaster Universities took 4D scans of 15 healthy fetuses. They found that fetuses develop from making very simple one-dimensional expressions at 24 weeks to complex multi-dimensional expressions by the time the mother is 36 weeks into her pregnancy.
The researchers suggest this is an adaptive process which enables the unborn baby to prepare themselves for life after birth when they have to communicate for example, if they feel hungry or uncomfortable, by facial or vocal expressions.
The study also found that fetuses observed at 24 weeks gestation rarely showed a combination of facial movements which could be recognised as ‘pain’ expressions. However, by 36 weeks gestation, a combination of at least four movements was seen more frequently.
Professor Alan Cameron, RCOG spokesperson, said:
“High quality 4D scans enables us to have a greater understanding of the unborn baby. The findings of this study are in keeping with previous research that has shown that the fetus does not respond to 'painful' or stressful situations until after 24 weeks gestation.
“In addition, this study adds to the literature supporting the evidence that fetal neurodevelopmental maturity is ongoing throughout gestation. More research is needed looking at a greater number of babies and looking in more detail at facial expressions, which will become easier as technology improves.”