DD (9 months) will go to bed, go to sleep and about an hour or 2 later she'll wake up screaming. By the time we run in there (within 15-20seconds) she's completely hysterical. We'll cuddle her and she'll generally go back to sleep within a few minutes.
It's horrible, to hear her do a high pitched distressed scream out of the blue.

Nightmares? Or what?

She's only really started in the last few months, since about 6 months. It only happens once a week to ten days.

Thanks!