Baby birth weight is determined by many factors. Some factors are hereditary and others are environmental - as in we can control them to a point. Sometimes weight is just a surprise.
Factors that can influence your newborn's birth weight...
His birth order: Most of the time firstborns are smallest, and consecutive siblings are bigger and bigger.
His gender: Baby boys tend to be larger than baby girls when all other factors are the same.
His status: Multiples (twins, triplets, and so on) are almost always smaller than single babies.
Your weight gain: The more you gain during your pregnancy the larger your baby is likely to be.
Your habits: If you smoke, take drugs, or drink too much caffeine, you may have a smaller baby.
Your health: If a mama has a condition like diabetes she's more prone to larger babies. Other conditions can affect baby size as well - your midwife or doctor can talk specifics with you.
Your baby's health: If your baby has a condition that equals poor health in the womb he may be born smaller.
Genetics: If women in your family have large babies, you may too. If they have smaller babies you might. OR you could blow the genetic code and have a baby who doesn't match any sort of genetic pattern so don't count on family to guess the size of your baby-to-be.
