NO, Dont ever try any diet pills during your pregnancy, it is highly dangerous as your baby may get affected by this pills, so waiting for few months after delivery, you can lose your weight.
I do not recommend any form of diet pills especially if you are pregnant. Increase your daily intake an additional 300 calories for the health of you and your baby. For example, if you are normally consuming 1800 calories + 300=2100 calories daily. This way you increase to the recommended weight gain of 25-35lbs but not gain 100+lbs. Exercising during your pregnancy would help keep your body toned, too. Hoped this helped you.