Because parents may share several residual confounders affecting the respiratory health of offspring, such as genetic, social, behavioral or environmental factors, researchers sought a way to assess the impact of “intrauterine programming” on the fetus.
They also wanted to see if the association between a mother’s experiences during pregnancy and worse respiratory health in preschool children continued to affect older children around the age of 10 years.
Researchers analyzed results from the parents of 4231 children drawn from an ongoing population-based prospective cohort study (Generation R) examining early environmental and genetic causes in growth and development.
Psychological distress in both parents was assessed by the Brief Symptom Inventory, a validated 53-item self-report questionnaire that asks about a range of psychological distress symptoms, including depression and anxiety, experienced in the last 7 days; it was taken both during and 3 years after pregnancy, and clinical cut-off values to determine severity of symptoms were developed.
Mothers were also asked to take the inventory at 2 and 6 months after pregnancy. Pediatric lung function was obtained by spirometry and asthma was assessed by questionnaire.
Of the participating parents, 362 (8.6%) mothers and 167 (3.9%) fathers reported depression and anxiety.
Of the children included in the analysis, researchers found the prevalence of current asthma at the age of 10 to be 5.9% (213 children). Factors included in the multiple regression analysis included, among others, age, ethnicity, smoking during pregnancy, and having a pet.
Overall maternal psychological distress during pregnancy was to children having a 45%-92% increased risk of asthma at age 10 for all measures of psychological distress (range, odds ratio [OR] 1.46; 95% CI, 1.12−1.90; OR, 1.91;95% CI, 1.26−2.91).
Spirometry tests revealed a lower forced vital capacity in 1 second (FVC1) (z-score 0.10; 95% CI, –0.20- –0.01) in children was associated with the maternal psychological issues seen during the pregnancy.
Depressive symptoms during pregnancy were associated with forced expiratory volume (z-score -0.13, 95% CI -0.24 − 0.01) and FVC (z-score -0.13 95%, CI -0.24 − -0.02).
Adjusting for maternal psychological distress post-pregnancy at 2, 6, and 36 months did not have an impact on asthma risk. Additionally, separating participants based on lifestyle, health-related factors, socioeconomic factors, and birth and early development factors did not have an effect.
Psychological distress in fathers during the pregnancy was not linked with asthma development in children.
However, researchers found that lifestyle and health-related factors did account for a reduction in how much of an effect maternal psychological distress had on forced expiratory flow after exhaling 75% of FVC.
“Our results may indicate an intrauterine effect of maternal psychological distress during pregnancy on fetal lung development and respiratory morbidity rather than an effect of unmeasured genetic, social, behavioural or environmental factors,” wrote the researchers.
The researchers suggested several possible intrauterine mechanisms that could influence fetal lung development and function, such as excess glucocorticoid production as a result of psychological distress, which can impair the development of the fetal hypothalamic–pituitary–adrenal axis and lead to maladaptive respiratory functioning.
Another potential reason for this association could be that the secretion of corticotrophin releasing hormones is disrupted as a result of the psychological problems in pregnancy.
While there were limitations to the study, the authors pointed out that it used a population-based cohort, but noted that additional research is needed.
Van Meel ER, Saharan G, Jaddoe VWV, et al. Parental psychological distress during pregnancy and the risk of childhood lower lung function and asthma: a population-based prospective cohort study. Thorax. Published online October 12, 2020. doi: 10.1136/thoraxjnl-2019-214099