Study finds new evidence that atopic eczema develops in the womb

Researchers have found new evidence that atopic eczema develops before birth and is linked to a child’s growth in the womb and shortly after birth. 

The study found that infants with eczema demonstrated altered patterns of growth during pregnancy, including impairment in growth of length starting in early pregnancy, prior to eczema becoming evident. The findings suggest that growth is impaired prior to the start of the disease process and its treatment, and that there are important influences acting during pregnancy on this common skin condition.

Within the Southampton Women’s Survey, a mother-offspring study, 1759 infants had serial measurements of their length, head and abdominal circumference during pregnancy at 11, 19 and 34 weeks, at birth, and at ages 6 and 12 months, and were assessed for eczema at ages 6 and/or 12 months.

Evidence of faltering growth in length from 11 weeks’ of pregnancy and shorter femur length, smaller abdominal circumference and a higher head to abdominal circumference ratio at 34 weeks’ gestation were associated with 20% or greater increased risks of eczema at age 6 months. Infants who had had a larger head circumference in early pregnancy and a declining abdominal growth velocity from 19 to 34 weeks of pregnancy had a 33% greater likelihood of eczema at age 12 months.

One possible explanation for these findings is “brain sparing” responses where the growth of the head and brain takes priority over the growth of the rest of the body. One organ that could be affected is the thymus, which is important in regulating the immune system, and this could result in an imbalance in immune cells and chemicals producing the inflammatory response seen in atopic eczema.

Dr Sarah El-Heis, the study’s lead researcher from the University of Southampton and the MRC Lifecourse Epidemiology Unit, said:

“Infants with eczema have an increased risk of impaired growth, which is a clinical concern that underpins recommendations to monitor growth in all infants with eczema. A number of reasons for the impaired growth have been proposed and include effects of the inflammatory process, topical corticosteroid treatment or an inappropriately restrictive diet. However, we have shown that infants with eczema at age 6 and 12 months have altered growth patterns before they are born and before eczema becomes evident, suggesting that there are important influences acting during pregnancy.”

Nina Goad, of the British Association of Dermatologists, said:

“Research into this common disorder has taken some interesting turns in recent years, with discoveries relating to birthweight, maternal socioeconomic status and even maternal mood during pregnancy impacting on risk factors. What is becoming clear is that there is no one, simple answer to why some babies develop eczema, and instead there is a complex interplay of factors, some of which are genetic and some of which are environmental. This study provides more data to help scientists explore the possible causes and how they may relate to one another.”