 Describe how the frequency of C-sections has changed over time
Incisions have been made in the lower part of the mother's abdomen and womb. I've pushed my gloved hand inside and managed to slide my fingers between the baby's head and the surrounding uterine tissue. 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. Its sole purpose was to test the effectiveness of a novel device called a Tydeman tube. Evolution has endowed us with heads proportionally so large that even when labour runs according to plan, the delivery process involves a bit of a squeeze. 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. 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." "We just observe that it happens… It's been discussed in the medical literature since the 1940s, but until 10 years ago, and throughout my training and most of my life as a consultant, it wasn't really talked about."
 The frequency has steadily increased
 The frequency has gradually decreased  The frequency has plateaued  The frequency has no significant trend  The frequency has steadily increased