According to a study by the College Board in the early 1980s, a trait known as "follow-through" was one of the best predictors of success in college and beyond.

WSJ: Jonah Lehrer Asks: What's College For? Is It Still Worth It? | Head Case

"We need to have predictors - when it will be a difficult birth, when a woman might go into early labour, for example, " Prof Wray says.

BBC: Making childbirth safer and easier for women