Its great to see some different portraiture from the usual.... refreshing, thanks.
Exposure: both shots suffer from burnt highlights. unfortunately all those burnt highlights are in the dress, her legs and face, which means that you lost all the toning and texture in the main focus point of your shot. If you shot in RAW you may be able to safe it, but there is nothing to be done in jpeg, just reshoot. The matrix exposure meter of your camera may have been fooled into overexposure by the dark background. Try to use centre weight metering on this. It does not matter if the background gets underexposed but you want to preserve all the information in the main subject.
Composition: I like the composition of the first one, she looks very happy with her unborn baby! So you got the story there. The overexposed dress makes her belly look like a white blob. A correct exposure would give you some tonality there, highligting the nice curves, really what you want when shooting a pregnant woman. A tighter crop or a crop that is a bit more off-centre would improve the photo as well.
thanks for posting and keep the photos coming
Not sure what the story is in the second photo. While i see a very happy Mom in the first, i wonder why she is looking into the skies in the second.... is she trying to find an answer there why she is pregnant? the composition of the second shot does not apeal to me at all.