Birth stage three, which begins after the birth of the baby, further contractions expel the placenta, amniotic sac, and the remaining portion of the umbilical cord usually within a few minutes. Enormous changes take place in the newborn's circulation to enable breathing in air. In the uterus, the unborn baby is dependent on circulation of blood through the placenta for sustenance including gaseous exchange and the unborn baby's blood bypasses the lungs by flowing through the foramen ovale, which is a hole in the septum dividing the right atrium and left atrium. After birth the umbilical cord is clamped and cut,
Umbilical cord prolapse at 5 minutes and length of hospitalization after delivery. While both measures are worse for newborns delivered after cord prolapse, it is unclear what effect this has in the long-term. Relatively large studies that have tried to quantify long-term effects of cord prolapse on children found that less than 1% (1 in 120 studied) suffered a major neurologic handicap, and less than 1% (110 in 16,675) had diagnosed cerebral palsy. Rates of umbilical cord prolapse ranges from 0.1-0.6% of all pregnancies. This rate has remained stable over time. A recent study estimates 77% of cord prolapses occur in singleton pregnancies,