It sounds like she's confused bedtime with a nap. First, at 3 am, don't jump up to respond to her. Wait ten minutes, to see if she lulls herself back to sleep. Then, if you have to get up, no excitement, no bright lights. Exaggerate the importance of being quiet, because it's night time. Then, examine the times she's been napping. If she's going down for her naps too early, be exciting around the time she gets sleepy for the nap, and try to move it back by 20 or 30 minutes each day. If she's taking particularly long naps, you may need to wake her after 2 hours to keep her in "nap" mode, rather than the deep sleep of night time. Also, wake her from an afternoon nap if it's going to mess up bedtime.
at 8:19 AM on Sep. 6, 2009