Preterm birth is a term commonly used for a baby who is born before 37 weeks. This has complication in lung development and can cause difficulty in breathing as they don’t develop fully. Steroid, short form of corticosteroids which are synthetic natural human hormones can be injected to a pregnant woman to overcome this problem.
Among all the corticosteroids, betamethasone is used followed by dexamathasone to a lesser extent as they are broken down to inactive metabolite such as cortisol by up to 50% compared to others which are broken down by 85% by the placental enzyme 11 ?-deoxygenase. Multiple courses of dexmethasone are associated with a risk of periventricular leukomalacia (PVL) and neurologic impairment.
Mode of action
The first step of a steroid hormone is to bind to a specific cytoplasmic receptor. The steroid-receptor complex formed migrates to the nucleus where it ultimately binds to the chromatin and initiated the characteristic biologic response.
Amount of surfactant produced in premature baby’s lung are increased, helping the neonatal lungs to stay open (Engle, 2008).
Steroids help the fetus to clear fluid out of their lungs more effectively (Jain &Eaton,2008).
Babies exposed to steroids around the time of delivery have more lung tissue. Babies with larger lung volumes are able to oxygenate their blood more easily.
Engle, W. A. (2008). Surfactant-replacement therapy for respiratory distress in the preterm and term neonate. Pediatrics, 121(2), 419-432.
Jain, L., & Eaton, D. C. (2006, February). Physiology of fetal lung fluid clearance and the effect of labor. In Seminars in perinatology (Vol. 30, No. 1, pp. 34-43). WB Saunders.