What if i reduce or cut out starches (potatoes, rice, etc.) will that make my tummy flatter?

Yes.: I assume you are on thyroid medication. During your pregnancy you should frequently have thyroid tests done as your dose of medication may need to be adjusted.

Less calories: Losing weight means less calories in than you need in a day. You may lose some from the tummy area. A high starch high calorie diet can contribute to fat deposition. Eating whole grains over processed foods in portion controlled amounts would be helpful while taking in less calories than you need.

If you lose weight: For flatter abdomen eat healthy & get physically active. Calories burned > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge & “bicycling” exercise on back. Engage in regular aerobic exercise (i.e. running, swimming, Nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.)