"It's a way of taking a picture of something using sound inaudible to the human ear," Tachibana explained, opening up a tall cabinet and pulling out a cart with the equipment on it. "Similar to sonar, if you're familiar with that at all, but on a detail scale, rather than a wide one. It has a fairly wide range of applications for monitoring the state of something inside the body, not just in pregnancy."

Which was why he was well practiced with it, despite not having first had experience directly with pregnancy.