Alexander weighed almost 10 pounds at birth. That put him in the top fifth percentile for weight, meaning he was bigger than 95 percent of newborn babies. Today at his eighteen-month checkup, his pediatrician comments that Alexander is now in the fiftieth percentile for his weight. Alexander’s adoptive parents ask whether they should be concerned that he has dropped to a lower percentile, but the pediatrician explains that many factors influence growth during the first few years of life, including multiple genes and environmental experiences. By toddlerhood, all these factors together will move most children into a percentile that will likely stabilize in later childhood.
The first two years of life are a time of incredible change. The earliest months can be a haze for many new parents and caregivers, who may be feeling sleep deprived and struggling to learn what their baby needs or wants. But a few months later, a baby who used to wake hourly may sleep for longer stretches. Caregivers find joy in the baby’s evolving smiles and coos. And two years later, that toddler may well tell grownups what they want or don’t want by saying a few words or running toward a favorite toy or turning away from a disliked food.
There are many typical changes in the first two years of life, starting with patterns of growth and maturation in weight, height, and head size. Additional considerations include sleep and feeding, important aspects of health and development at any age, and moving on to brain growth and health risks. Moreover, cultural, social, and other experiences may influence maturation in these areas.
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Footnotes
-
1
This
study (Barry, 2021) uses the term "Western."
-
2
This
study (Giannotti & Cortesi, 2009) uses the term “Anglo European.”
-
3
This
study (Bains & Mittal, 2023) uses the term "Western."