Morphing animations are usually good at capturing viewers' attention, and yours was no exception. Unfortunately, it was short-lived, and a bit disappointing, as I expected it to go on after the fetus, but it stopped abruptly instead.
I have to admit though, it was fun while it lasted and I couldn't help thinking how much better it would have looked in color. Artistic feel of black and white does make an impact, but adding those fills would make it look finalized. After all, you already had those neatly connected lines out there!
The last thing I would like to note is how cheap the tweened objects looked compared to the frame-by-frame-animated bits. It worked nicely when all those little things were moving on stage simultaneously, but when applied to the jaw in the beginning, made the whole skull look flat.
Other than that, it went along well with the music and overall this little experiment can be called a success, so I'm rating it 10 just to motivate you to keep working on your skills and continue to make improvements in flash!