hello welcome to health care magic. the weight of the fetus depends on the maternal intake of food and also the genetic constitution of the baby. your gynaecologist can tell you by a clinical examixation if your baby is growing adequately for its size. also the ultrasound will tell you the approximate baby weight, which should correspond to your weeks of pregnancy. if all that is fine you need not worry. the baby should be healthy rather than fat/heavy weight. meanwhile you should take good intake of proteins in your diet along with proteinex powder (two spoons) three times a day with milk. also take good amount of vegetables.