Adjustable Elastic for Maternity Trousers (or Growing Children!) - A tutorial

I recently made a couple of pairs of trousers for my pregnant daughter. For one pair, the pattern I was using required you to thread elastic in through the waist band. This was to be via the usual method of sewing up the waistband apart from leaving a couple of inches not sewn, through which you can thread the elastic with a safety pin, sewing the two ends of the elastic together, and finally sewing up the last bit of the band.

However, I was concerned that if the elastic was tight enough to hold the trousers up early in the pregnancy, it would be too tight later on.

To find out how I have solved this, read on.



So I invented a method to get round this. (When I say invented, I mean I had to think this out for myself, I hadn't read the idea anywhere else. It's not to say someone else didn't invent it as well!) It has resulted in a band which was snug enough to hold up only a few months in, but will hopefully continue to expand as she does, without becoming constricting or uncomfortable.

I used a piece of 'normal' elastic (about 3/4" width) round the back, measured as a comfortable length to go round the back of her waist. Having measured her back waist, deducted a couple of inches or so, to allow for the fact that you need a bit of stretch. I then joined it to a piece of buttonhole elastic for the front, the same width  (about 3/4"), this I left fairly loose (i.e. longer than the back). I threaded it through the waistband, having left a slit in both side seams of the waistband, and joined the other ends of the two elastics together. I finished the edges of these slits but left them open. I then sewed a button on each side underneath the elastic, so that the button hole elastic could be pulled up tighter to start with, and fastened onto the buttons, and then gradually released as the tummy expands. The idea is to button the elastic twice, once, near the end to stop it slipping back through the waistband, and the second time, to hold it at the length you want for a comfortable fit. It can be adjusted at both the left and right hand side.

Here you can see the effect on another pair of trousers. The button hole elastic is joined at both ends to the other elastic, which is slightly shorter than the back waistband. It has here been pulled through, so the button is first put through the hole nearest where this elastic joins the other elastic. This fixes the stretch on the back elastic. It could be changed of course by first putting the button through a different hole, but I'm assuming there is not too much increase in the girth of the back in pregnancy. Then the button hole elastic is pulled through the slit a bit more, forming a flat loop, and the button is put through a button hole further along to tighten the front elastic.  This happens on both sides of the trousers. Here, it is quite a short loop, implying that the elastic is almost at its greatest extent now. But early in pregnancy, you could have it tightened more to hold them up! Eventually you could unbutton all of it if you wanted. 

This seem to have worked well, so I also did the same on other pairs of trousers I made from a modern maternity pattern that made no mention of elastic, but which were very loose at the waist and which tended to slip down rather embarrassingly.

Of course, you can use this method on any pair of trousers for which you want to allow waist expansion, for example for a child. You wouldn't necessarily need to fix the back waist stretch then. You would just pull up the elastic as much as required. And you may just be able to put the button hole elastic just on one side, or at the back, with a smaller waistband.

Incidentally, it would be possible to use button hole elastic all the way round, so you only had one join in the elastic. I didn't do that for two reasons. One, it tends to be more expensive than ordinary elastic, so I chose to use it sparingly as needed. The other more important reason, though, is that I have generally found it to be more stretchy (looser) than normal elastic and I thought it might stretch too much on the back. As it happened, this wider button hole elastic was pretty similar stretchiness-wise to the normal elastic, so in practice I didn't I gain much there. But I liked being able to 'fix' the back elastic.