Whirly in over eleven I have had two patients who produced their first babies very quickly. One knew she was pregnant and had been attending regular antenatal appointments the other was as 16 years old who said she didn't know she was pregnant but in a quiet conversation with her a couple of days later admitted she had known but was too ashamed / frightened to tell her parents (who turned out to be very supportive) so had carefully put it to the back of her mind until it could no longer be ignored. I used to wonder how people could not know they were pregnant until the night I had a fire (caused by a lightning strike). It was 02:00 and I stood at the bottom of the stairs looking at the smoke pouring under the living room door and thinking "No, it isn't happening" a thought that lasted a millisecond before the more rational "Get back upstairs and phone the Fire Brigade" took over. I realised then that it was simply because it was an immediately life-threatening situation that I reacted by calling the Fire Brigade but that I could now see why young, pregnant teenagers, and also older mums, could manage to persuade themselves that they were not pregnant as they would not perceive pregnancy as being immediately life-threatening and would be able to ignore all the signs and symptoms until the baby made an appearance.