HMD occurs when there is not enough chemical substance called surfactant in the lungs. Surfactant is made by the cells in the airways and consists of phospholipids and protein. It begins to be produced in the fetus at about 24 to 28 weeks of pregnancy, and is found in amniotic fluid between 28 and 32 weeks. From about 35 weeks gestation, most babies have developed adequate amounts of surfactant.
HMD occurs in about 60 to 80 percent of babies born before 28 weeks gestation, but upto 30 percent of those born between 32 and 36 weeks also get HMD.
Although most babies with HMD are premature, other factors can influence the chances of developing the disease. These include:
While each baby may experience symptoms differently, some of the most common symptoms of HMD include:
Symptoms of HMD usually peak by the third day. The support needed may be in the form of NICU, oxygen, CPAP or mechanical ventilation.
As with any disease, more severe cases often have greater risks for complications. Some complications associated with HMD include:
Air leaks of the lung tissues such as:
Prevention of HMD: