Answer to Question 1
D
Although surfactant normally begins to be secreted in the lungs at 28 weeks gestation, it takes at least another 8 weeks for sufficient surfactant to be secreted and distributed throughout the alveoli. Adrenal cortical steroids and alpha-fetoproteins are appropriate causes for neonatal respiratory distress but are not the most likely cause in this situation. Also, amino acids is not the primary reason for neonatal respiratory distress in a preterm neonate.
Answer to Question 2
4
Rationale:
1. In partial previa, the placenta only partially covers the internal os.
2. In low-lying previa, the placenta is in the lower uterine segment in close proximity to the cervix.
3. In marginal previa, the placenta just touches the edge of the internal os.
4. Complete placental previa occurs when the placenta completely covers the internal cervical os.