question:  What percentage of cesarean births in the UK every year are classified as emergencies?
context: Obstetrics for beginners It's my first go at delivering a baby by caesarean section – and the foetal head is impacted, jammed in its mother's pelvis. Incisions have been made in the lower part of the mother's abdomen and womb. She comes with a vulva, a pre-cut incision in her abdomen and, most importantly, a uterus containing a foetal head that should, in the normal way of things, be free to emerge between her legs. For the baby's head to get stuck on the way out may not be usual, but it's by no means a rarity. The standard response is to perform a caesarean section. Every year some 160,000 babies are born in the UK this way, with almost two thirds of them classified as emergencies. One audit has suggested that roughly 8,000 babies get stuck and have to be delivered by caesarean at a stage when their mothers are fully dilated. "Some of the babies will be so close to coming out by the normal route," says Tydeman, "that it's then difficult to get them back up and remove them through the hole in the woman's tummy." Considering the universality of childbirth, impaction and the best way of dealing with it are topics that seem to have gone remarkably unstudied. "There are strong opinions about why it happens and what to do, but very little research evidence," says Tydeman, adding that many of these opinions are contradictory. In a protracted birth that's destined to end with a caesarean, the longer the labour is allowed to go on before the obstetrician decides to intervene, the greater the likelihood that the baby's head will become impacted. However, concern over the rising number of babies born by caesarean has made doctors more wary of doing them – one consequence of which is that medical staff may allow a difficult birth to continue for longer before they resort to surgery. When obstetricians doing planned caesareans slice open a mother's womb, what they usually see is the baby's head.
output:  Nearly two thirds
options:  Nearly one half  Nearly two thirds  Nearly one quarter  Nearly three quarters