What Are The Side Effect Of Duphaston?

hi im 12 weeks and 1 day pregnant had my scan yesterday and my Ob saw like a halo/bubble around my baby s head she said she does not know what it is she suspects fluid and that the skull could be too thin , i did a bit of research on the net and i found none she will refer to another doctor but i am too scared, is it a side effect of duphaston? she put me on duphaston for two weeks because i was having a focal uterine contraction on my 9th week - 10 week please help me just to ease my mind and monday i hope i can get something out of her... h/b is good baby s active its just the fluid/halo/bubble around the head. :(