Chiffon Knit has some stretch. If you're between sizes and prefer a tighter fit, you might want to size down from your typical size.
Our maternity dresses are designed to accommodate most baby bumps to full-term. We suggest choosing your size based on what you expect your bust measurement will be at the time you'll wear your dress. You may want to size up from your current bust measurement depending on how far along you are in your pregnancy.