I'm 13 weeks, had my 1st trimester NT screening ultrasound Monday and both babies were great, healthy heartbeats around 160, moving, plenty of fluid, and all measurements were normal.  Tuesday I basically lounged all day long and went to bed, nothing unusual.  Woke up on and off during the night, but that's not unusual.  Felt trickling of what I thought was discharge and went back to sleep.  Woke up fully in the morning to go to work and was in a puddle of blood, soaked through my boxers and onto the sheets.  My husband immediately took me to the ER.  Ultrasound showed both babies with healthy heartbeats and nothing unusual, and pelvic exam showed my cervix closed and nothing unusual.  I am relieved beyond measure that everything is ok, but still worried because an OB specialist doc who saw me said they don't know if this was a threatened miscarriage or just something that I will have to deal with throughout my whole pregnancy.  She said some pregnancies have this just once and then are ok and some have it the whole time and are ok, and then some pregnancies have no symptoms and have miscarriages.  This was a bit frustrating and I was so scared and horrified that something major was wrong because of the amount of blood.  And weirdly enough, no more bleeding today.  Anyone else have this or heard of this?  What went on with your pregnancies?  She did say spotting and cramping is common with twin pregnancies, but it's so frustrating not knowing where the bleeding Was coming from.