<Tr> <Th> Frequency </Th> <Td> ~ 15 million a year (12% of deliveries) </Td> </Tr> <Tr> <Th> Deaths </Th> <Td> 805,800 </Td> </Tr> <P> 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 . </P> <P> The cause of preterm birth is often not known . Risk factors include diabetes, high blood pressure, being pregnant with more than one baby, being either obese or underweight, a number of vaginal infections, tobacco smoking and psychological stress, among others . It is recommended that labor not be medically induced before 39 weeks unless required for other medical reasons . The same recommendation applies to cesarean section . Medical reasons for early delivery include preeclampsia . </P>

When is a baby said to be premature