I use average weights to give you an idea of about how large your baby is at a particular time. Because growth is rapid during pregnancy, infants born prematurely may be very small. Even a few weeks' less time in the uterus can have a dramatic effect on the size of your baby. The baby continues to grow after 36 weeks of gestation but at a slower rate. A couple of interesting factors have been identified with regards to the birth weight of your baby.
Boys weigh more than girls.
Birth weight of an infant increases with the increasing number of pregnancies you have or the number of babies you deliver. These are general statements and don't apply to everyone, but they appear to apply in most cases. A baby born between the 38th and 42nd weeks of pregnancy is a term baby or full-term infant. Before the 38th week, the term preterm can be applied to the baby. At 42 weeks of pregnancy, and after this time, postterm is used.