I think she is having a boy.

I actually think this will be a girl. Seem to recall
something about: If you got a butt (or popo) during your pregnancy,
it's a girl. If not, it's a boy. Very scientifical of course.

Another hint is how you carry it: If the baby lies vertical,
buy blue, if horisontal, pink...or in Mary's case beige.
It's not obvious from these pictures but I have seen others
where it's more apparent.
Normally I hate the sight of pregnant women in tight dresses,
but she makes it work somehow. Very chic

DoS