Rett Syndrome Growth Chart: Monitoring Height and Weight

Tracking a child’s growth helps healthcare providers, parents, and caregivers tell if a child is meeting growth and development milestones on time. This is important even when a child has a condition that affects growth and development, such as Rett syndrome.

If a child with Rett syndrome doesn’t reach expected milestones on time, it may raise questions or concerns about their health. Growth delays can also be among the first signs of Rett syndrome that a parent or caregiver notices.

In this article, we explain growth charts, key measurements to track, and ways Rett syndrome can affect growth in children and teens.

Why Standard Growth Charts Might Not Work

Many healthcare providers use standardized growth charts to track a child’s measurements over time. The Centers for Disease Control and Prevention (CDC), the World Health Organization (WHO), and other organizations provide these charts to show how a child compares to others of the same age and sex. These charts can help detect slowed growth as early as possible.

For children with Rett syndrome, standard growth charts may not give a clear picture. Their measurements often fall at the low end or below the typical range for their age. Because children with Rett syndrome tend to grow at a slower rate, a standardized chart may not be as useful for tracking their growth and development.

Girls with Rett syndrome tend to fall below average in weight by about 6 months and in height by about 13 months, and they often don’t have the typical growth spurt around puberty, according to the International Rett Syndrome Foundation. Even with enough nutrition and proper medical care, many remain below the second percentile on standardized growth charts at age 12.

Rett Syndrome Challenges

Standardized growth charts may not work well for children with Rett syndrome because of challenges linked to the condition. A child may be at the lower end of average or below average in height and weight for several reasons.

Slower Growth

In children with Rett syndrome, brain growth slows starting early in life. Over time, their head circumference (measurement around the head) and body growth also slow. This can lead to lower height and weight compared with others of the same age and sex.

Feeding Challenges

Some children may be smaller due to their nutritional status. Rett syndrome can cause problems with chewing and swallowing, which can make it hard to get enough calories to grow at a typical rate for their age.

Low Muscle Mass

Low muscle mass is also a common sign of Rett syndrome. On average, muscle makes up about 25 percent of an infant’s body weight and 40 percent of an adult’s weight. When muscle mass is low, overall body weight is also lower.

Tracking a Child’s Own Trends

Because of slower growth, feeding difficulties, and lower average muscle mass, standard growth charts may not reflect a child’s expected growth. It may be more helpful to track a child’s measurements over time to see their own growth pattern, rather than focusing on percentiles and comparing to averages.

There are also growth charts designed for people with Rett syndrome. Your child’s pediatrician may be able to provide these.

When and What To Measure

Medical experts recommend measuring a child every six months from infancy to age 12, then once a year. Healthcare providers monitor the following measurements in children with Rett syndrome:

Length or Height

Babies with Rett syndrome usually have a typical length for their age until about 15 months, but then their growth starts to slow down. A 10-year study found that people with Rett syndrome have slower growth over time and are often shorter than peers of the same age and sex.

Weight

Like height, weight is often typical during the first 15 months in children with Rett syndrome. After that, their weight tends to slow down compared to that of other children.

Body Mass Index

Body mass index (BMI) is calculated using height and weight. Average BMI may be similar between children with and without Rett syndrome. However, the range is wider, suggesting that children with Rett syndrome are more likely to be overweight or underweight for their height.

Head Circumference

Head circumference is often the first measurement to show slower growth. A smaller-than-average head size can appear as early as 1 month of age. By age 2, head size is often below the second percentile on standard growth reference charts.

A child’s head growth rate can offer some insight into their brain development. In general, doctors measure children’s head circumference regularly until about 3 years of age.

Recognizing Red Flags While Measuring Growth

When tracking a child’s growth and development, certain red flags can point to growth delays. Not every below-average measurement indicates Rett syndrome or another condition that delays growth. However, some growth chart patterns warrant close attention. Parents and caregivers should look for signs and symptoms such as:

• Growth pattern changes — If a child’s measurements drop to lower percentiles than before, their doctor might recommend testing for Rett syndrome or other conditions.
• Coughing or choking during meals — If a child has trouble eating because of reflux or problems with chewing and swallowing, they may not be getting enough nutrition.
• Weight gain outpacing height or length — If a child gains weight faster than they get taller, a doctor may want to look more closely at overall growth patterns.
• Stalled weight gain — If a child doesn’t gain much weight between check-ins, it may also suggest delayed growth.

Keeping Measurements Reliable

When measuring children with Rett syndrome at home, consistency can help you spot changes over time more clearly. These tips can help you keep weight measurements accurate:

• Use the same scale each time.
• Place the scale on a firm, even surface.
• Use a digital scale, if possible, instead of a spring-loaded one.
• Make sure your child wears similar clothing each time, without shoes or heavy layers.
• Weigh the child at about the same time of day.
• Round the recorded weight to the nearest decimal place.

Talk to Your Doctor

Parents or caregivers who notice signs of delayed growth in an infant or child should talk with a doctor or pediatrician as soon as possible. The doctor can recommend next steps, such as diagnostic testing for Rett syndrome or approaches to support better nutrition, such as:

• Consultations with a dietitian
• Swallow studies
• Feeding strategies to prevent choking or vomiting
• Medical treatment for common gastrointestinal issues like acid reflux and constipation
• Increased calorie or protein intake

Doctors can also help you decide if and when a feeding tube may be needed to support nutrition and lower the risk of choking.

Join the Conversation

On MyRettTeam, people share their experiences with Rett syndrome, get advice, and find support from others who understand.

Do you use any other methods for tracking height and weight in people with Rett syndrome? Let others know in the comments below.