Is Aspartame Safe?
Aspartame -- commercially called NutraSweet and found in many diet sodas, sugar-free foods, and the sugar substitute Equal -- appears to be safe for most pregnant women. However, women with an inherited inborn error of body chemistry called phenylketonuria (PKU) should avoid foods and drinks containing aspartame.
In 1998, the Food and Drug Administration (FDA) approved a new sweetener called sucralose for use in a wide variety of foods and drinks. This sweetener, which is made from sugar, is safe for everyone, including pregnant women, according to the FDA. Still, since the long-term effects of sucralose are not yet known, it's best to opt for natural sweeteners when possible.