Every woman and pregnancy differs. Generally a woman who is carrying her first child shows and gains weight slower and wont "look pregnant" until 6 months. A woman who has previously had children will show sooner since the muscles in her stomach are already weakened from a previous pregnancy and can start looking pregnant as soon as 3-4 months. Weight gain all depends on the woman though...some women are all stomach and barely gain weight at all while others will gain 30+ pounds.
Around 4 months and weight gain is slow at first then increases as the pregnancy progresses
everyones diff some could be at 3 months others at 4 or 5 ...