Objectives:To study the effects of ambroxol on prevention of premature babies with pulmonary hyaline membrane disease(HMD)with prenatal corticosteroids.

• 目的:研究在应用肾上腺糖皮质激素的基础上加用盐酸氨溴索(沐舒坦)预防新生儿肺透明膜病的效果。