So let’s get to it.
Step 1: Select a Pair of Pants
With the success at my first try, I quickly decided to modify two pairs of pants I wore during my previous pregnancy. They have thick and short bands which I found not comfortable at all. I can’t believe how they have worked previously. So I removed the thick elastic bands and replaced with tall bands of soft knit fabric which covers the whole bump just like the pants I tried in store.
So in one afternoon of a weekend, I changed from having zero pairs of comfortable maternity pants to having 3 pairs.
Another good thing about the maternity pants with stretch band that covers the whole bump is it smoothes out the bump. With a loose fitting shirt on top, it prevents you from spilling the beans before your pregnancy is well established and you are ready to make the announcement. Of course, I spill the beans here by posting this Instructables before I'll make announcement off internet.
Step 2: Take Measurements and Cut the Fabric
Get [ A” + ¼” (bottom seam allowance) + 1 ¼” (top seam allowance and elastic casing band) + 2” extra ] stretch knit fabric from a fabric store
Cut a piece of the stretch fabric of ( A” + ¼” + 1 ¼” ) by (B” – 1”), make sure the stretch direction is across your body not up and down your body, that is, stretch direction is along measurement B.
Step 3: Remove Waist Band From Pants and Fix/trim the Front Line
For the suit pants, I pushed the zipper pull head all the way to the bottom;
slip stitch closed 2” of the zipper fly opening;
mark 1/4" above the closed zipper fly opening at center front;
draw a gradual curve from the marked point at center front to the top of the sides;
trim the front of the pants along the drawn line.
For the two pairs of old maternity jeans, I needed only to remove the waist band.
The following steps were done the same way for the suit pants and jeans. Photos show only one in progress.
Step 4: Trim the Stretch Knit Fabric
Draw a line on the fabric from the lowest of center front to the top of sides, ¼” over the front of the pants. (I used a piece of ¼” wide elastic as a guide.)
Fold the fabric along the center line.
Trim along the drawn line.
With right side together, serge the center back of the fabric so it becomes a tube now.
If you don’t have a serger, you need to use a stretch stitch on your sewing machine or stretch the fabric by hands if your sewing machine doesn’t have a stretch stitch. It’s tricky to sew stretch fabric without a serger.
Step 5: Sew the Stretch Band to the Pants
Serge the seam. Again if you don’t have a serger, you need to use a stretch stitch on your sewing machine or stretch the fabric by hands if your sewing machine doesn’t have a stretch stitch.
Fold the band up. You can try on at this point to make sure there is nothing off. Mine seemed great.
Top stitch close to the fold.
Fold in 1 ¼” on the top of the stretch band to form elastic casing, pin in place.
Stitch the elastic casing in place with ¼” seam allowance with a stretch stitch or stretch the fabric by hands if your sewing machine doesn’t have a stretch stitch. It’s essential to use stretch stitch or stretch fabric by hands in this step.
Use a seam ripper, on the front inside of the elastic casing band, open a ¾” slit, hand serge the slit with buttonhole stitch. Cut a piece of ¾” wide elastic of (B” – 1”) long, thread it through the casing, overlapping the ends for at least 1”, stitch the ends together.