percentage of babies born at 24 weeks that survive
Fetal viability There is no sharp limit of development, gestational age, or weight at which a human fetus automatically becomes viable.[1] According to studies between 2003 and 2005, 20 to 35 percent of babies born at 23 weeks of gestation survive, while 50 to 70 percent of babies born at 24 to 25 weeks, and more than 90 percent born at 26 to 27 weeks, survive.[4] It is rare for a baby weighing less than 500 g (17.6 ounces) to survive.[1] A baby's chances for survival increase 3-4% per day between 23 and 24 weeks of gestation and about 2-3% per day between 24 and 26 weeks of gestation. After 26 weeks the rate of survival increases at a much slower rate because survival is high already.[5][6][7][8]
Preterm birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks' gestational age.[1] These babies are known as preemies or premies.[1] Symptoms of preterm labor include uterine contractions which occur more often than every ten minutes or the leaking of fluid from the vagina.[8] Premature infants are at greater risk for cerebral palsy, delays in development, hearing problems and sight problems.[1] These risks are greater the earlier a baby is born.[1]