Why are premature babies at risk?

Premature babies, regardless of the severity of the prematurity, are at risk of serious morbidity due to RSV compared to babies born on time. (full term)
Deficient pulmonary development is expressed in the pulmonary volume and limited surface area and wall thickness of the lung tissues, as can be seen in the attached tables:

Lung maturity in the different weeks:

The increased risk of RSV morbidity stems directly from 2 main factors:

1. Lack of antibodies transferred to the fetus through the umbilical cord (maternal antibody)
2. Visual development is lacking and limited.

Deficiency in the amount of antibodies transferred to the fetus from the mother

The passage of the antibodies through the umbilical cord occurs in the third trimester after the 28th week of pregnancy.
The level of antibodies at birth is directly related to the week of pregnancy at birth, in addition the level of antibodies is affected by birth weight.
It can be seen that the level of antibodies even at 32-35 weeks is lower in 50% than those of a baby born on time.
Also, only in the 37th week of pregnancy, the level of antibodies is above the desired norm.

The level of antibodies that are transferred to the baby from its mother is lower in 53% premature babies than in full-term babies

Visual development is lacking and limited

Premature babies' lungs are not fully developed at birth. Although the lung tissues are present in some premature babies until the 32nd week, they are not fully developed until the 36th week of pregnancy.