a friend on the craftster forum asked for help making adjustments to her bodice patterns to accomodate a full tummy. in her case, she likes to buy patterns that fit in the shoulders and neck but they are not big enough in the tummy. there are many ways to fix this, but since my friend is just starting out learning how to adjust patterns, i'll show the simpler versions for now.
the basics of the adjustment are the same no matter whether the tummy is larger due to pregnancy or some other factor: you add length to the center front--because a curved line is longer than a straight line, so you need a longer center front to go over your curvier tummy--and then you widen the hemline so the front will reach around enough to meet the back without dragging the side seam forward.
please note--you must always work with patterns that have no seam allowances! you add them back on when all your adjustments are complete. also, i highly recommend you make a tracing of your original pattern and do your adjustments on that--save our original in case you need to start over again. :)
the first pattern she showed me is a simple tunic with bust dart:
adding length to the front is simple--you just make the center front line longer. :) the average is 2"-4" but you can lengthen as much or as little as needed (click any image to see an enlargement):
now, you could just add width to the sides but you sometimes end up with the same side seam problem i mentioned in my post about skirt hems--the side seam length changes. the way around this is to slash the pattern from the hemline up to BUT NOT THRU the end of the bottom dart leg. the top of the slash will act as a hinge. you then pivot the tiny side section out, opening a wedge that gives more room at the bottom. making the adjustment in this manner preserves the fit of the bust, shoulders, and neck and adds room only where needed. the amount you open depends on how much extra room you need, the average is 2"- 4" but you can do as much or as little as you require:
then you draw a new, curved hemline. NOTE: the hemline has to come out from the center front being completely horizontal or you'll end up with a pointy front. once you get the horizontal established, you just make a curve that is pleasing to the eye:
the other pattern she asked for help with is a surplice bodice with an empire waistline, bust darts converted into gathers and a slightly flared lower bodice:
the adjustment for this design is similar to the one for the tunic. first you lengthen the center front, then you slash the lower bodice from the hem up to BUT NOT THRU the empire waistline, pivot the side section, and draw a new hemline. it doesn't really matter where you make the slash, as long as it is parallel with the center front line:
i want to emphasize that this is not the only way to do this! its just the way i like to do it.
as in my post about skirt hems, all the images in this post (with the exception of the pattern examples missteri gave me) were created using the software i use when teaching patternmaking at fashion design online. the basic principles for making patterns are the same no matter whether you use paper and pencil, or a CAD engine, so go get your patterns out and start slashing!