Final answer:
Infants born between 20 and 36.6 weeks of gestation, regardless of outcome, are considered pre-term and may have low birth weight.
Step-by-step explanation:
The number of infants born between 20 and 36.6 weeks of gestation, regardless of outcome, can vary. Generally, infants born before full term, which is defined as 36-40 weeks after fertilization, are considered pre-term. These infants are usually smaller than full-term infants because they have spent less time growing in the uterus. Pre-term birth is one of the major causes of low birth weight, which is defined as a birth weight lower than 2.5 kg (5.5 lb.).