Hmmm... DO you still have a nurbs version? The problem comes in when you converted to polys... If you plan on converting to Sub D's There are some things to take into consideration... It really needs to be a clean mesh, with as many quads as possible... Definetly nothing more than 4 sides. Kinda like a English Essay when they say "no forms of B allowed" Get what I am saying? Its one of the most important rules to a nice clean Sub d mesh. Anyways... The best way to convert from Nurbs to Sub D's is to take your Nurbs Surface and rebuild the surface to a higher # when you are finnised modeling it. Lets say 20X20 (depends on your model) then convert using Controll Points. . Witch can be good because you can control how many polys alot quicker,but it really rounds everything out and you loose alot of detail. Look at the pic below, the first Shape is Nurbs.The second is the standard way of converting it to Polys, like you did with your fetus. the Third way is by controll points.The final way that I have posted is when you convert using control points. In my opinion that is probably the best way to do it. So.. I would Highly recomend trying one of the last two ways of converting from Nurbs to Polys, and it should work fine, plus you will have a much nicer looking Sub D mesh with out all of the Wrinkles (hopefully) Hope this helps, let me know...
Brian
Hope this helps?

Brian