# When should I worry about Rett Syndrome at 3–6 months?

Canonical: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-3-to-6-month-old-might-have-rett-syndrome
Publisher: Pinnacle Blooms Network / Bharath Healthcare Laboratories Private Limited

Rett Syndrome is rarely identifiable at 3–6 months, because its hallmark is a later loss of skills after a period of normal early development — usually after 6–18 months. At this age, simply track ordinary milestones like eye contact, head control and babble, and seek prompt review if your baby ever goes backwards. A focused Rett assessment becomes meaningful later and is confirmed only by a clinician with genetic testing — never an online form.

*If your baby is 3 to 6 months old and you've read something frightening about Rett Syndrome, take a breath — what you're feeling is love, not failure, and the timing here matters enormously.*

## In short
In most cases, Rett Syndrome (ICD-11 LD90.0) is **not something that shows itself clearly between 3 and 6 months**. The hallmark of classic Rett Syndrome is a period of apparently normal early development followed by a *regression* — a loss of skills already gained — and that turning point usually appears later, most often after 6–18 months. At 3–6 months, the kindest and most useful thing you can do is simply track your baby's ordinary milestones and bring any genuine concern to a clinician — not search for a diagnosis that cannot meaningfully be made this early. This is reassurance with watchfulness, not a verdict.

## What is actually appropriate to watch at 3–6 months
Rather than hunting for signs of a specific rare condition, gently notice the broad, joyful building blocks of these months:

- **Eye contact and social smiling** — does your baby look at you and smile back?
- **Head control** steadily improving when held or during tummy time
- **Reaching and grasping** for objects, beginning to bring hands to the mouth
- **Cooing and babbling**, turning towards your voice
- **Settling and feeding** in a fairly predictable rhythm

These are the things that tell us development is unfolding. A single "off" day is not a worry — babies vary hugely. What clinicians pay attention to is a *persistent* pattern, or — importantly with Rett Syndrome — a **loss of skills your baby once had**, such as stopping using the hands, losing babble, or a slowing of head growth. If you ever notice your child go *backwards* in any area, that is the moment to seek a prompt review, at any age.

## When a Rett assessment becomes meaningful
Because Rett Syndrome is defined by regression and emerging hand-use difficulties, a focused evaluation usually becomes meaningful **after the first 6 months and into the second year**, when the developmental picture is clearer. It is a genetic condition (most often linked to the MECP2 gene) and is confirmed through clinical assessment and genetic testing arranged by a paediatrician or developmental specialist — never from a checklist or an online form. If you have a strong family history or a specific clinical worry now, raise it directly with your paediatrician, who can decide whether earlier review is warranted.

## The Pinnacle way
A clinical [AbilityScore®](/ask/what-is-the-abilityscore-and-how-is-it-calculated) and any diagnosis are formed only at a Pinnacle Blooms Network centre, under qualified clinician care — never from an online form or a checklist. Across 70+ centres in 4 states, our clinicians look at your baby's *whole* developmental story with warmth and patience, not labels. If something feels off, a calm [developmental check](/rett-syndrome) and gentle [early intervention](/early-intervention-therapy) support are always there for your family.

## Trusted sources
WHO ICD-11 (LD90.0, Rett Syndrome); American Academy of Pediatrics developmental milestone guidance (healthychildren.org); CDC "Learn the Signs. Act Early." milestone resources (cdc.gov).

**Next step —** Trust your instinct without alarm: note your baby's milestones, and if anything worries you — especially a loss of skills — [book a developmental check](https://www.pinnacleblooms.org/enroll-autism-speech-aba-therapies-india) with a Pinnacle clinician.

This is general information, not a diagnosis — individual assessment and diagnosis require an appropriately qualified healthcare professional.

## Sources
- WHO ICD-11: Rett Syndrome: https://icd.who.int/
- AAP — developmental milestones (HealthyChildren.org): https://www.healthychildren.org/
- CDC — Learn the Signs. Act Early.: https://www.cdc.gov/child-development

## Connected topics and perspectives
- Conditions: https://pinnacleblooms.org/ask/conditions
- Parent: https://pinnacleblooms.org/ask/lens/stakeholder/parent
- Infant-3-6: https://pinnacleblooms.org/ask/lens/age/infant-3-6
- Context: https://pinnacleblooms.org/ask/lens/domain/context
- Concern: https://pinnacleblooms.org/ask/lens/intent/concern
- Screen: https://pinnacleblooms.org/ask/lens/lifecycle/screen
- Special Education: https://pinnacleblooms.org/ask/lens/route/special-education
- Early Clarity: https://pinnacleblooms.org/ask/lens/empowerment/early_clarity

## Related question paths

### Understand the subject
- How Rett Syndrome Affects a Child's Daily Life: https://pinnacleblooms.org/ask/how-does-rett-syndrome-affect-a-child-s-daily-life
- Is Rett Syndrome considered a disability?: https://pinnacleblooms.org/ask/is-rett-syndrome-considered-a-disability
- Is Rett Syndrome Genetic or Hereditary?: https://pinnacleblooms.org/ask/is-rett-syndrome-genetic-or-hereditary
- What are common myths about Rett Syndrome?: https://pinnacleblooms.org/ask/what-are-common-myths-about-rett-syndrome
- Types and Stages of Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-types-or-levels-of-rett-syndrome
- What causes Rett syndrome in children?: https://pinnacleblooms.org/ask/what-causes-rett-syndrome-in-children
- What is Rett Syndrome?: https://pinnacleblooms.org/ask/what-is-rett-syndrome
- What is Rett Syndrome, and what does it look like in early childhood?: https://pinnacleblooms.org/ask/what-is-rett-syndrome-and-what-does-it-look-like-in-early-childhood
- Conditions That Occur Alongside Rett Syndrome: https://pinnacleblooms.org/ask/what-other-conditions-often-occur-alongside-rett-syndrome
- Early Intervention Outcomes in Rett Syndrome (Under 7): https://pinnacleblooms.org/ask/what-does-current-research-show-about-early-intervention-outcomes-for-rett-syndrome-in-children-under-7
- What is Rett Syndrome, and its ICD-11 features in early childhood?: https://pinnacleblooms.org/ask/what-is-rett-syndrome-and-what-are-its-icd-11-features-in-early-childhood
- ICD-11 Classification of Rett Syndrome (LD90.0): https://pinnacleblooms.org/ask/what-is-the-icd-11-classification-for-rett-syndrome

### Recognise signs & concerns
- When to worry about Rett syndrome at 6–9 months: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-6-to-9-month-old-might-have-rett-syndrome
- Early Signs of Rett Syndrome in a 3-to-6-Month-Old: https://pinnacleblooms.org/ask/what-are-the-early-signs-of-rett-syndrome-in-a-3-to-6-month-old
- When should I worry that my 9-to-12-month-old might have Rett Syndrome?: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-9-to-12-month-old-might-have-rett-syndrome
- When should I worry that my 3-year-old might have Rett Syndrome?: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-3-year-old-might-have-rett-syndrome
- When to worry about Rett Syndrome at 12–18 months: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-12-to-18-month-old-might-have-rett-syndrome
- When should I worry that my newborn might have Rett Syndrome?: https://pinnacleblooms.org/ask/when-should-i-worry-that-my-newborn-might-have-rett-syndrome
- Can Rett Syndrome Be Cured?: https://pinnacleblooms.org/ask/can-rett-syndrome-be-cured
- Can Rett Syndrome Be Prevented?: https://pinnacleblooms.org/ask/can-rett-syndrome-be-prevented
- Rett Syndrome in Boys: https://pinnacleblooms.org/ask/do-boys-show-rett-syndrome-differently
- Do girls show Rett Syndrome differently?: https://pinnacleblooms.org/ask/do-girls-show-rett-syndrome-differently
- Should I be worried my child might have Rett Syndrome?: https://pinnacleblooms.org/ask/should-i-be-worried-my-child-might-have-rett-syndrome
- Early Signs of Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-early-signs-of-rett-syndrome

### Explore causes & influences
- Are boys more likely to have Rett Syndrome?: https://pinnacleblooms.org/ask/are-boys-more-likely-to-have-rett-syndrome
- Are girls more likely to have Rett Syndrome?: https://pinnacleblooms.org/ask/are-girls-more-likely-to-have-rett-syndrome
- What Causes Rett Syndrome in Young Children?: https://pinnacleblooms.org/ask/what-causes-rett-syndrome-in-young-children
- Early Intervention for Rett Syndrome, UNCRPD & the SDGs: https://pinnacleblooms.org/ask/how-does-early-intervention-for-rett-syndrome-advance-un-child-rights-uncrpd-and-the-sdgs
- Known contributing factors for Rett Syndrome: https://pinnacleblooms.org/ask/what-are-the-known-contributing-factors-for-rett-syndrome-in-early-childhood
- Cost-effectiveness of early therapy for Rett Syndrome in young children: https://pinnacleblooms.org/ask/what-is-the-cost-effectiveness-of-early-therapy-for-rett-syndrome-in-young-children
- Prevalence and Public-Health Burden of Rett Syndrome in India: https://pinnacleblooms.org/ask/what-is-the-prevalence-and-public-health-burden-of-rett-syndrome-among-young-children-in-india

### Understand assessment
- How AbilityScore Tracks Progress in a Child with Rett Syndrome: https://pinnacleblooms.org/ask/how-does-abilityscore-track-progress-in-a-child-with-rett-syndrome
- How Rett Syndrome Is Assessed in a Young Child: https://pinnacleblooms.org/ask/how-is-rett-syndrome-assessed-in-a-young-child
- How Rett Syndrome Is Assessed in Children Under 7: https://pinnacleblooms.org/ask/how-is-rett-syndrome-assessed-in-children-under-7
- What an AbilityScore® of 0–100 means for a child with Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-0-100-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 100–200 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-100-200-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 200–300 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-200-300-mean-for-a-child-with-rett-syndrome
- AbilityScore 300–400 in Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-300-400-mean-for-a-child-with-rett-syndrome
- What an AbilityScore of 400–500 Means in Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-400-500-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 500–600 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-500-600-mean-for-a-child-with-rett-syndrome
- What does an AbilityScore of 600–700 mean for a child with Rett Syndrome?: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-600-700-mean-for-a-child-with-rett-syndrome
- What an AbilityScore of 700–800 Means for a Child with Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-700-800-mean-for-a-child-with-rett-syndrome
- What an AbilityScore of 800–900 Means for a Child with Rett Syndrome: https://pinnacleblooms.org/ask/what-does-an-abilityscore-of-800-900-mean-for-a-child-with-rett-syndrome

### Explore therapy & support
- Can a Child with Rett Syndrome Attend a Mainstream School?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-attend-a-mainstream-school
- Can a Child with Rett Syndrome Attend a Regular School?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-attend-a-regular-school
- Can a Child with Rett Syndrome Live Independently?: https://pinnacleblooms.org/ask/can-a-child-with-rett-syndrome-grow-up-to-live-independently
- How is Rett Syndrome diagnosed in a child?: https://pinnacleblooms.org/ask/how-is-rett-syndrome-diagnosed-in-a-child
- How is Rett Syndrome supported through therapy?: https://pinnacleblooms.org/ask/how-is-rett-syndrome-supported-through-therapy
- Rett Syndrome AbilityScore®: What to Do Next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-0-100-what-should-we-do-next
- Rett Syndrome with an AbilityScore of 100–200: your next step: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-100-200-what-should-we-do-next
- Rett Syndrome: AbilityScore 200–300 — what to do next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-200-300-what-should-we-do-next
- Rett Syndrome: AbilityScore 300–400 — what to do next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-300-400-what-should-we-do-next
- Rett Syndrome with an AbilityScore of 400–500: what to do next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-400-500-what-should-we-do-next
- Rett Syndrome and an AbilityScore of 500–600: What To Do Next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-500-600-what-should-we-do-next
- Rett Syndrome AbilityScore 600–700: What To Do Next: https://pinnacleblooms.org/ask/my-child-with-rett-syndrome-has-an-abilityscore-of-600-700-what-should-we-do-next

### At home & in everyday life
- How can I support my child with Rett Syndrome at home?: https://pinnacleblooms.org/ask/how-can-i-support-my-child-with-rett-syndrome-at-home