Although caesarean sections made up only 5% of all deliveries in the early 1970s, among women who did have primary caesarean sections, the century-old opinion held, "Once a caesarean, always a caesarean." Overall, cesarean sections became so commonplace that the caesarean delivery rate climbed to over 31% in 2006. A mother-driven movement supporting VBAC changed standard medical practice, and rates of VBAC rose in the 1980s and early 1990s. However, a major turning point occurred in 1996 when one well publicized study in "The New England Journal of Medicine" reported that vaginal delivery after previous caesarean section resulted in more maternal complications than a repeat caesarean delivery. The American Congress of Obstetrics and Gynecology subsequently issued guidelines which identified VBAC as a high-risk delivery requiring the availability of an anesthesiologist, an obstetrician, and an operating room on standby. Logistical and legal (professional liability) concerns led many hospitals to enact overt or de facto VBAC bans. As a result, the rate at which VBAC was attempted fell from 26% in the early 1990s to 8.5% in 2006.