I think the finished project might be too large because of its extreme stretchiness. But I might be able to pull it off because she will be 5 months pregnant and she might appreciate the "give" and since it is so lightweight she will need it to be cool as she can be. I can remember the Summer that I carried her now husband - I thought I would die from the heat of the pregnancy and the Summer heat combined together. The previous 2 pregnancies were Winter babies and I learned to appreciate them. LOL
Then after I have sewn the parts all together I go back and serge the the ends of the sleeves and the bottom of the tail of the shirt. This is just to make it look cleaner when you put your hems in and it also helps guide you down your road!