Limit refined sugars as much as possible during pregnancy to avoid serious conditions including gestational diabetes, preeclampsia, and babies with high birth weight.
Good options to refined white sugars include honey, maple syrup and raw sugar in moderation and agave. Try to avoid all artificial sweeteners including aspartame, saccharine, Splenda, Stevia and Sucralose, etc. These sweeteners may have less calories or effect on blood sugar but they are artificial and may potentially be unhealthy to you and your baby.
Although Aspartame and Splenda and Stevia have been cleared by the FDA, they are to be used in moderation during pregnancy, but please do try to limit their use.