This is a very easy project if you have a sewing machine and basic sewing skills.
One pair of jeans that fit you well before you were pregnant
One t-shirt that fit you very snugly before you were pregnant (maybe even a size too small)
Scissors, seam ripper, pins
Sewing machine, coordinating-colored thread
Piece of soft elastic long enough to go around your hips or above your belly
Step 1: Start with jeans and a t-shirt.
The jeans should have fit you well before you were pregnant, and the t-shirt should be very snug.
Step 2: Cut the top off of the t-shirt just below the armholes.
Discard the top (sleeves and neck) or save it for some other project. Keep the nice tube bottom.
Step 3: Unsew the bottom of the back belt loops using the seam ripper.
Make any adjustments you want to the jeans. I never liked these pocket flaps, so I am taking them off (with the seam ripper as well).
Step 4: Cut a curve across the front of the jeans.
First, pull the zipper closed. Then, cut across the front of the jeans: start about 1/2 inch below the waistband on the side, curve down to about half-way down the length of the zipper, then curve back up to 1/2 inch below the waist band.
Be conservative here. You can always cut more off if you need to. Try to cut across areas that have less fabric/decoration (e.g. above the coin pocket, but below the waistband/belt loops).
Pin the fly closed and the pockets in place.
Step 5: Cut straight across the back of the jeans.
Cut about 1/2 inch below the waistband. This is why you unattached the bottom of the belt loops in step 3.
Step 6: Machine baste across the front curve.
This is to hold the pockets, fly, and zipper in place. Do this part carefully so that you don't break a needle on the zipper.
Step 7: Put the jeans on to check the fit.
They should sit just below your pregnant belly (or where you think it will be).
Step 8: Prepare to sew the t-shirt.
Cut a corresponding curve on the part of the shirt that is going to be the back. Slip the shirt over the jeans and pin the raw edges together, matching side seams and center front and back.
If you plan to pull the shirt up over your belly, then pin the right side (outside) of the shirt to the right side (outside) of the jeans. If you plan to wear these under your belly, then pin the wrong side (inside) of the shirt to the right side (outside) of the jeans.
Step 9: Sew the t-shirt to the jeans.
Machine sew near the edges of the fabric using a fairly wide, short zigzag stitch. Be careful when you get to the zipper. I lifted my needle and presser foot, and skipped that 1/4 inch to avoid damaging the machine. Also, be careful of any rivets. Go all the way around twice, a little lower the second time. Trim as needed.
Step 10: Elasticize the casing.
If you plan to pull the shirt up over your belly, measure a piece of elastic the right length, and slide it through (the ready-made) casing that used to be the hem of the shirt. If you plan to fold the shirt down under your belly, measure around your hips and do the same thing. You will probably need to make a small opening in the hem to do this.
Step 11: All done!
Finished upcycled maternity jeans. I plan to pull this shirt up over my belly as I'm nearing the end of my pregnancy, but this is how it looks folded underneath. (Note that if I wanted to keep it down most of the time, I should have sewed on the shirt inside out).
Be creative! You can use this technique with slacks and skirts as well.
Visit my blog to see what other fun craftiness I'm up to: http://www.karenelisam.blogspot.com/