Vaginal birth after caesarean (VBAC) refers to the practice of elivering a baby vaginally (naturally) after a previous baby has been delivered through caesarean section (surgically). . A caesarian section leaves a scar in the wall of the uterus. This scar is weaker than the normal uterine wall, so if the woman goes in labor in a subsequent pregnancy there is a higher than normal risk of a ruptured uterus, a catastrophic complication. Because of this risk an attempt at normal vaginal delivery was for most of the 20th century considered unacceptably risky. This opinion was challenged by many studies showing that many women with previous caesaran sections did have successful vaginal deliveries. In the 1980s and 1990s there was a strong movement to encourage attempts at vaginal delivery after caesarean section. For a while some regulatory bodies in the US monitored the percentage of those women with previous caesareans who were offered vaginal delivery, using this number as a measure of the quality of obstetrical care. Studies in the 1990s confirmed that vaginal delivery after previous caesaran section was indeed much riskier than average. The American College of Obstetrics and Gynecology issued guidelines which identify VBAC as a high-risk delivery requiring the availabilty of an anesthesiologist, an obstetrician, and on operating room on standby (Int J Gyn Obs; 1999; vol 66, p197). In the 1990s the rate at which VBAC was tried fell from 26% to 13%.