This is what I have come up with. Does it sound ok?
Dear Parents,
I hope that everyone has started the New Year off well. Some of you may not be aware that I am pregnant and am about to take a few weeks off for maternity leave. My intentions are to work until February 10th, at which point a substitute will take over for me. I plan to return in mid March, barring any complications.
In my absence Mrs. M will be working with your children. She has substitute taught for me on a few occasions this school year and has come highly recommended by Mrs. G. Prior to my absence, Mrs. M will be in the classroom getting to know the students and what their specific goals and objectives are. I am confident that she will do a wonderful job while I am away, and if she has any questions she has Mrs. G, Ms. C, and Ms. L at hand to help as needed.
During my absence I plan to check my email regularly, if you have any questions you can contact me at ------. You can also contact Mrs. G as she is very knowledgeable about your children and their specific needs.
Thank you so much for your support.
I teach special education in an inclusive classroom so there will still be another teacher and 2 aids in the classroom while I am out.