Two things that stick out to me are the shape of the belly and the arm she's resting on. In this case the belly looks more like a beer belly than pregnant belly as it hangs fairly low. As for the arm, while there would be foreshortening, the elbow should be out further. You can check by resting your head in your hand and seeing how your arm sticks out. Also, the shoulder seems high.

About the breasts, they're alright assuming they'll be held in place. Otherwise they should likely droop a bit more.

It's hard to see in this piece, but it seems like her head is not centered. You'd either have to bring her right shoulder down or move her head up.

Hope this helps.

Thank you. :) I'm not sure what to do with the belly. She'll be farther down in the finished picture, so mayhaps that will help with the angle. The other things I can work on. I sketched this looking at a picture of a woman, but I will work on some of those things. Thank you!

I notice that this is pretty good on the anatomy. the breasts are about the only thing I see odd.

This image looks heavily referenced and the reason I say this is because there proportions are good, the linear contours are good, but none of it is well understood and clarity of the contours completely evaporates once the forms become complex and pushed into perspective. Such as in the elbow or when volume needs to show. Plus the lines are hairy and lack confidence and lose any sense of overlap.
I don't suggest anyone who doesn't know better reference photos mainly because the camera eye warps the figure and landscape in general.
So if this is referenced, keep that in mind.
if not, then you need to learn how to better structure what your drawing, thinking about the underlying forms that are going to create what you see on the surface.

To ground her she needs a sense of gravity. Like she's being pulled down. SO having the breasts fall towards earth is a good way to go. Even push her tummy down that way. But not too much! Pregnant bellies are obviously not made of fat and it has to retain a solidity that wouldn't be seen in fatty tissues such as the breasts.

In the taily part, construct in geometric shapes the form going back into space and then fill it in. This will get you that sense of depth like the tail is further behind her. And avoid showing leg lack anatomy, once your in her lower region think fish.

Overlap and wrapping lines in the face, torso, and arms will give it rhythm, help depth, and give us the idea that this figure has angles and planes and the ability to move.

http://postimage.org/image/2g0jgm1k4/

It was referenced and heavily at that, you've got a good eye. :) And your suggestions and redlines are -so- helpful! I can see what I did wrong now and can fix that before I ink! Thank you!!

The nose doesn't usually have a visible line up the side, unless there's a bold shadow making one or the face is turned aside.

The lines seem very precise and deliberate. This might be a purely aesthetic point, but loosening up the wrist and using smooth pencil strokes for curves makes for much more fluid and expressive lines.

For the record: I highly applaud your use of reference. The hands are nice. It might be an idea to find a particular type of fish to use as reference for the tail fin.

One difference between fat and pregnancy is that the belly is more smooth and round, and all the mass is localized in front. There's less mass around the obliques and upper thighs.

I think this is superbly done.
Myself, I would round out the belly, give it a more beach ball type shape, and, personally I would remove the line near the naval area. This for me is what makes it seem most like fatty tissue, and not pregnancy. The elbow looks a bit off, but I myself have no clue how to fix it. I also think the tail perhaps tapers too quickly, not sure tho.