I got a question for you: Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks' gestational age. These babies are known as preemies or premies. Symptoms of preterm labor include uterine contractions which occur more often than every ten minutes or the leaking of fluid from the vagina. Premature infants are at greater risk for cerebral palsy, delays in development, hearing problems and sight problems. These risks are greater the earlier a baby is born.

Based on this passage, when is a baby said to be premature?
Let's think first:
To answer this question, we should know that: Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks' gestational age.
Therefore, the answer is fewer than 37 weeks ' gestational age.