Biological explanation of lower birth weight from smoking during pregnancy
Groningen: New-born babies of smoking
mothers weigh on average 200 grams less than the babies of non-smoking
mothers. Nearly 20 percent of this lower birth weight can be accounted
for by the change in DNA methylation of the GFI1 gene as a result of
smoking during pregnancy. This is the conclusion of a study conducted at
the University Medical Center Groningen. According to the study, these
findings are confirmed by research conducted by the Erasmus MC in
Rotterdam and the University of Bristol in England. The researchers are
publishing their results this week in the International Journal of Epidemiology.
In a genome-wide methylation study among 255
children, the researchers investigated whether smoking during pregnancy
leads to differences in DNA methylation in the child’s umbilical cord
blood. DNA methylation changes the extent to which genes are expressed
without changing the DNA itself. This change in gene expression can in
turn result in other changes, such as a lower birth weight.
Lower birth weight
Earlier studies showed that exposure to cigarette
smoke during pregnancy can change the child’s methylation pattern. Thus
far it was not known whether these changes in DNA methylation could also
account for the lower birth weight. The present study shows that
children of smoking mothers are on average 202 grams lighter at birth
and that 12 to 19% of this lower birth weight can be accounted for by
differences in DNA methylation of the GFI1 gene. The GFI1 gene plays a
role in growth and development.
Cardiovascular diseases
‘Our study clearly shows the negative effects of
smoking during pregnancy for the child’s development. A too low birth
weight increases the risk of developing conditions such as
cardiovascular diseases or diabetes at a later age. It goes without
saying that these negative effects can be prevented if pregnant women
are made aware of the importance of quitting smoking. We therefore hope
that our study can contribute to partially clarifying the biological
effects of smoking during pregnancy,’ says Leanne Küpers, PhD students
who conducted the study. She also found that other genes are impacted by
smoking during pregnancy. ‘But in the context of our study, these genes
did not seem to account for the lower birth weight.’
GECKO Drenthe Study
The study forms part of the GECKO Drenthe Study. This
large-scale study follows 2,900 children born in Drenthe in 2006 and
2007. In close collaboration with GGD Drenthe (Municipal Health Centre),
the researchers carry out frequent length and weight measurements and
investigate lifestyle factors. The study aims to identify which factors
play a role in the development of overweight in children.
