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Growth and Your Newborn


The main job for newborns is to grow. And in the first year, they do it in a big way. In that time most babies triple their birth weight and increase their length by about 50%.

From your newborn's

  • Size of parents. Tall parents may have larger-than-average newborns; short parents may have smaller-than-average newborns.
  • Multiple births. If you're having twins, triplets, or more, you can count on your babies being relatively small. Multiples not only have to share their growing space in the uterus, they also are often born early, which leads to small size at birth.
  • Birth order. First babies are sometimes smaller than brothers or sisters born later.
  • Gender. Girls tend to be smaller, boys larger, but the differences are slight at birth.
  • Mother's health during pregnancy. Certain illnesses and habits can affect the weight of a newborn. Factors that can lead to a lower birth weight include a mother's high blood pressure, heart problems, or use of cigarettes, alcohol, or illegal drugs during the pregnancy. If the mother has diabetes, the baby may have a higher birth weight. All conditions that can affect a baby's weight should be closely monitored by the mother's doctor. In addition, women should not smoke, drink alcohol, or use illegal drugs during pregnancy.
  • Nutrition during pregnancy. Proper nutrition is essential for a baby's growth in the uterus and beyond. A poor diet during pregnancy can affect how much a newborn weighs and how the infant grows.
  • Baby's health. Medical problems, including some birth defects and certain infections acquired during the pregnancy, can affect a child's birth weight and later growth.
  • Growth and Premature Babies

    Mary L. Gavin, MD
    Date reviewed: August 2005

    What should you expect as your child grows? Learn how to understand and deal with your child's changing body and mind from infancy through the teen years.

    Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

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