Should i be worried if i am a smoker and at 20 weeks my baby is 10 ounces?

Stop smoking: If you are concerned about low birth weight in your child, you MUST make every effort to discontinue your smoking. However, 10 oz. at 20 weeks is within the normal range for fetal development. Smoking reduces blood flow to the placenta, and does far more potential damage than just low birth weight, which is serious enough in its own right. Talk to your OB provider about smoking cessation help.