You are going to need to cut out two matching rectangles to be the main body of your top/dress. One will be for the front and one will be for the back. To determine how big to make these rectangles take measurements of the following:
waist (esp. if you are pregnant)
Whichever one is the largest will be used to determine the width of your rectangles.
For instance. Let's pretend that my hips are the widest portion of my body and by measuring all the way around the widest part of my hips (front and back) it came to 40". I would add 3" for seam allowance and 2" for ease making my total 45". Now I would divide that by 2 (half for front and half for back) so that each of my rectangles would be 22 1/2" wide.
To determine the length of the two rectangles use your measuring tape to measure from the nape of your neck to wherever you want it to end and then add on about 5 inches to make sure that you have plenty of extra fabric to hem etc...
Here is a pic of my two rectangles folded in half. My belly was the widest portion and I wanted the length to end a little above my knees so my finished measurements went as follows:
waist = 47" circumference + 3" seam allowance + 2" ease = 52" / 2 = 26" width for each rectangle
length = about 35" desired + 5" = 40"
so I cut 2 identical rectangles at 26" x 40".
Now it's time to cut the neckline:
Depending on whether you want a boatneck, or deep neckline you can adjust accordingly, but here are my measurements.
First fold both of your rectangles in half length wise. Now measure and mark 4 1/2" across and 3 1/2" down. Draw a sloping line like the photo above and cut creating a half circle when unfolded. (These measurements give me a least 1" of ease around my head when pulling it on and off. My head circumference measures 22". If yours is a lot bigger than that you may want to add another inch to one of the measurements to give you a little more room.)
You should have quite a bit of extra fabric at this time. Keep this fabric as you will be using it to make the ruffles and the waist tie if you decide to do those.
*check back in a couple of days and we will finish up the neckline.