009. The effect of maternal asthma during pregnancy on placental function, fetal growth and childhood development

Abstract

Fetal growth and neonatal birth weight are significant contributing factors to the development of adult disease states in later life. In human pregnancy, we have identified sexually dimorphic differences in fetal growth with the female fetus reducing growth in response to maternal asthma and the male fetus continuing to grow at a normal rate but being at an increased risk of in utero death. The physiological mechanisms that confer sex-specific differences in the fetal response to maternal asthma are unknown. However our research has identified differences in mechanisms associated with fetal glucocorticoid regulation, which are also associated with changes in childhood growth patterns. Asthmatic and control pregnant women were recruited at their first antenatal visit and followed through to delivery. Subjects were assessed for severity of asthma and their use of medication, including glucocorticoid therapy, was recorded. In addition to routine antenatal care, fetal growth was determined using Doppler ultrasound. Following delivery placentas and cord blood were collected. The children of the women followed during the study were examined by a paediatrician at 6 months of age and every 12 months after that initial visit. Our data shows that in response to maternal asthma, the female fetus has an increase in cortisol, which downregulates placental GR expression, immune and hypothalamic-pituitary-adrenal function and is associated with decreased growth. The male fetus responds to increased cortisol with an increase in GR expression and no change in HPA or immune function or growth. These data indicate that the male and female fetus have different strategies to control growth and in their response to a maternal stress, such as asthma.