Why frustrate yourself by trying to expand waistlines with elastic bands and open buttons? With the exception of a few people, buying maternity clothes will be inevitable. The more wear you are able to get out of them, the better your investment will be. So, as soon as you can't zip up your favorite pair of jeans, treat yourself to the comfort of maternity jeans - topped with your everyday button down white oxford, no one will know the difference, but you will certainly feel it!

Source: http://pregnancyfashion.com/tips/look/94.htm