Babies who are much smaller or larger than average in weight and length are more likely to experience health complications.
However, there is a wide variation of healthy birth weights, so caregivers may not need to worry. A doctor will assess how closely they need to monitor a baby’s growth over time.
Growth rates for length are fairly predictable among babies in the first year of life. Doctors are more interested in a baby’s growth pattern than their length.
A baby whose growth slows down such that they fall to a much lower length group, or whose length is persistently at a lower level, may have a health issue.
According to Centers for Disease Control and Prevention (CDC), a child who falls below the fifth percentile may have an abnormal growth pattern.
Numerous factors affect a child’s height. Genetics play a major role, and children are likely to be a similar height to their parents.
However, this may not be apparent right away, as a baby who will be a tall adult may have a shorter length at birth and in the first year or two of life.
Other factors affecting a baby’s length and overall size later on include:
- Nutrition. The consumption of healthy food supports healthy growth.
- Hormones. Some children with hormonal imbalances grow slowly or more quickly than their peers.
- Health. Some children with certain genetic conditions, such as Down syndrome, may be smaller than others. Certain health conditions, such as juvenile arthritis, can also affect growth.
- Medication. Some medications, such as steroid drugs including prednisone, may stunt growth.
People often do not see the effect of these issues on height in the first year of life.