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]
Amniotic fluid The volume of amniotic fluid increases with the growth of fetus. From the 10th to the 20th week it increases from 25ml to 400ml approximately.[citation needed] Approximately in the 10th-11th week the breathing and swallowing of the fetus slightly decrease the amount of fluid, but neither urination nor swallowing contributes significantly to fluid quantity changes, until the 25th week, when keratinization of skin is complete. Then the relationship between fluid and fetal growth stops. It reaches a plateau of 800ml by the 28-week gestational age. The amount of fluid declines to roughly 400 ml at 42 weeks.[2] There is about 1L of amniotic fluid at birth.[1]