This is my first pregnancy from using Clomid.  I just got my 2nd blood drawn my first levels were at 49, & 4 days later (today) they were at 344!  I'm only just shy of 3 weeks.  I know they said they like to see the numbers double each time,  & once I'm at 1600 I can have an ultra sound.  With the numbers jumping so much, could be twins?  Any insight on this would be much appreciated!!