The allowable weight gain for a pregnant woman is about 25 to 30 lbs. I discouraged you to lose weight during 1st trimester because it is the time where organneosis and brain development is taking place. Eat a nutritious well balanced diet and dont forget to take your OB vitamins with 400 mg of Folic acid to prevent neural defects.Some safe methods of losing weight is to cut off your carbs and sugar in the diet especially if you have gestational diabetes. Or limit sodium intake to decrease water retention.