According to research presented at the 2016 European Respiratory Society, reduced fetal size is linked to an increased asthma risk as well as reduced lung function in children ages 5 to 15 years. According to Science Daily, the study suggests that antenatal factors in the pregnant mother contribute to the life-long respiratory wellbeing of the child. For the study, the researchers tested the hypothesis that reduced fetal size would be associated with reduced lung function and persistent asthma from 5 to 15 years of age. A total of 2,000 mothers were recruited from the antenatal clinic in Aberdeen between 1997 and 1999.

Fetal size in the first trimester (T1) and second (T2) trimester was determined by routine ultrasound scan. Lung function and asthma status were determined at ages 5, 10, and 15 years, and various modeling and statistical techniques were then applied to the data. The authors of the study discovered larger fetuses were at reduced risk for asthma and had better lung function. Fetal size was expressed as a z score, which is a statistical method of expressing difference from normal (four z scores covers the range from abnormally small to abnormally large).

Each z score increases in T1 size was associated with an overall 22% reduced risk for asthma between ages 5, 10, and 15, which is a result that applied even after adjustment for confounding factors. The research revealed that increased fetal size was associated with increased lung function, which was independent of confounding factors. Persistent asthma was associated with reductions in T1 and T2 size and FEV1 at ages 5, 10, and 15 compared to the two other groups, reports Science Daily.

“First trimester fetal size — a surrogate for fetal lung size — is relevant to symptoms and respiratory physiology through to 15 years of age. These findings suggest that antenatal factors contribute to life-long respiratory wellbeing,” explains Dr Stephen Turner of the University of Aberdeen. “What we need to do now is first replicate these findings in other cohorts and then work out whether it is fetuses which start off small and stay small who have the worst outcomes or whether it is those that start off normal size (before 10 weeks) and then become small who are in trouble.”

Turner adds, “Ultimately, any intervention is going to boil down to mothers not smoking or drinking, having a balanced diet and taking regular exercise — but this is good incentive for a healthy maternal lifestyle!”

Source: Science Daily