Here's a way to stop that row from getting narrower: If you find that the item you're making gets narrower as you go along, you are probably missing a crochet stitch in the last stitch of each row (a common beginner mistake). Try counting stitches for awhile and you'll know if you are ending up with one less stitch on every row. Then you can correct that by making a special note to notice what the last stitch of the row should look like and being careful to crochet into that last stitch of the row each time.