Beckwith-Wiedemann Syndrome: The Overgrowth Condition That Makes Babies Larger at Birth — and How Care Keeps Most Children Healthy for Life

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick answer

Beckwith-Wiedemann syndrome is a rare genetic overgrowth disorder in which most babies are born larger than normal [1], often with a large tongue or low newborn blood sugar. It carries about a 7.4% chance of certain childhood cancers [1] [2], so routine screenings are needed. There is no cure, but most children reach average adult height and have normal life expectancy [1].

What the research says

According to PubMed:

• Cancer risk differs by the type of chromosome 11 change. In a systematic review and meta-analysis of 1,370 patients with BWS, 102 developed tumors (7.4%). Tumor prevalence was 2.5% in ICR2 loss of methylation, 13.8% in paternal uniparental disomy, 22.8% in ICR1 gain of methylation and 8.6% in CDKN1C mutations. Wilms tumor was strongly linked to ICR1 gain of methylation (OR 68.3) and uniparental disomy (OR 13.2). The authors proposed screening targeted to the molecular subgroup. (Mussa et al., J Pediatr, 2016) [2].

• Assisted reproduction was linked to a roughly 10-fold higher BWS risk in one Italian study. In Piemonte, Italy, between 2005 and 2014, BWS birth prevalence was 1 in 1,126 after assisted reproductive techniques versus 1 in 12,254 after natural conception (relative risk 10.7, 95% CI 4.7–24.2). The study was retrospective and based on 38 BWS patients. (Mussa et al., Pediatrics, 2017) [3].

• A large Swedish registry found a smaller, less certain link. Among 2,084,127 liveborn singletons, the overall risk of an imprinting disorder was higher after ART (HR 1.84, 95% CI 1.38–2.45), but after adjusting for parental factors the BWS-specific excess risk could not be distinguished from chance (wHR 1.80, 95% CI 0.99–3.28). The combination of ICSI and cryopreserved embryos was associated with a higher BWS risk (wHR 6.69, 95% CI 2.09–21.45). (Ye et al., Fertil Steril, 2024) [4].

Study details are from PubMed abstracts.

What is Beckwith-Wiedemann syndrome?

Beckwith-Wiedemann syndrome (BWS) is a rare genetic disorder that affects your child's growth. It can affect many different parts of your child's body. Most babies with BWS are larger than normal (macrosomia). Some may be taller than other children their age. But your child's growth should slow down by the age of 8. They should be of average height in adulthood [1].

BWS is also known as Beckwith-Wiedemann spectrum. This is because the symptoms and their severity vary widely. The condition can affect many different parts of your child's body. Your child may have only one or many of its characteristics. Beckwith-Wiedemann syndrome also increases your child's risk of developing certain childhood cancers [1].

There's no cure for Beckwith-Wiedemann syndrome. But there are many treatments available to correct physical differences and relieve your child's symptoms. BWS usually doesn't cause any serious medical issues. Life expectancy is typically normal [1].

How common is Beckwith-Wiedemann syndrome?

BWS is described as a rare genetic disorder. The condition affects many different parts of the body, and every child's experience is unique — which is why providers call it the Beckwith-Wiedemann spectrum.

What are the characteristics of Beckwith-Wiedemann syndrome?

Beckwith-Wiedemann syndrome symptoms can vary widely from child to child. Your child may have only one or many of its characteristics. The features of BWS include abdominal organs that develop outside the belly (omphalocele), an abnormally large tongue (macroglossia), above average birth weight (above the 95th percentile), an enlarged liver (hepatomegaly), kidney abnormalities, low blood sugar (hypoglycemia) in the newborn period, one side of the body larger than the other (hemihyperplasia), tiny creases or indentations on the earlobes, and a tissue bulge around the belly button (umbilical hernia) [1].

What cancers are children with BWS at risk of developing?

Overall, children with BWS have about a 7.4% chance of developing cancer, with almost all of the risk increased between birth and the age of 8. These cancers include adrenocortical carcinoma, hepatoblastoma (liver cancer), neuroblastoma, rhabdomyosarcoma, and Wilms tumor [1].

What causes Beckwith-Wiedemann syndrome?

The causes of Beckwith-Wiedemann syndrome are complex. Researchers link most cases of BWS to certain epigenetic changes on chromosome 11. These changes affect the normal expression of genes on the portion of chromosome 11 (11p15.5) that controls growth. This is called genomic imprinting [1].

About 85% of children born with Beckwith-Wiedemann syndrome don't have a biological family history of the condition. Instead, the epigenetic changes happen randomly [1].

About 10% to 15% of children have a family history of Beckwith-Wiedemann syndrome. That means one parent passed down a genetic change that causes BWS [1].

In about 14% to 20% of children, testing does not find the genetic change behind the diagnosis (these children are also counted in the groups above) [1].

What are the risk factors?

Research into the cause of Beckwith-Wiedemann syndrome shows that people who use assisted reproductive technology (ART) to conceive may have a higher risk of having a baby with a genomic imprinting disorder like BWS. These ART procedures include in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) [1]. Scientists have to do more research to find the connection.

In addition, studies suggest that BWS is more common in twin pregnancies than in pregnancies with just one fetus [1].

What are the complications?

Beckwith-Wiedemann syndrome can lead to preterm labor. After your baby is born, they can develop breathing and feeding difficulties, low blood sugar (hypoglycemia) and cardiomyopathy [1].

Complications that can occur from childhood through adulthood include calcium deposits in the kidneys, cognitive impairment, kidney cysts, kidney stones, male infertility, scoliosis, speech issues, and urinary tract infections [1].

How is Beckwith-Wiedemann syndrome diagnosed?

Your healthcare provider may be able to diagnose Beckwith-Wiedemann syndrome before birth. Using a prenatal ultrasound, they can detect features of the condition, including enlarged kidney (nephromegaly), enlarged placenta, increased amniotic fluid around the fetus (polyhydramnios), larger fetus size than expected, macroglossia, and omphalocele [1].

If the ultrasound reveals potential signs of BWS, your provider can use prenatal genetic tests to confirm a diagnosis. These tests include amniocentesis and chorionic villus sampling [1].

After birth, your provider can diagnose or confirm the condition with a physical examination and genetic testing [1].

How is Beckwith-Wiedemann syndrome treated?

Beckwith-Wiedemann syndrome can affect many different parts of your child's body. Because of this, you'll work with many healthcare providers and specialists to address the specific symptoms and conditions affecting your child.

Macroglossia, or an enlarged tongue, is a common feature of BWS. A larger tongue size can cause sleeping, feeding and speaking issues. So, providers may use various treatments, including continuous positive airway pressure (CPAP) to treat obstructive sleep apnea and other sleep issues, specialized nipples or a nasogastric tube for feeding issues, speech therapy for speech difficulties, and tongue reduction surgery [1].

Other Beckwith-Wiedemann syndrome treatment options may include IV (intravenous) glucose, frequent feedings and certain medications to treat hypoglycemia; medications, surgery or other interventions to treat cardiac, gastrointestinal and kidney issues; orthotics or surgical correction to reduce the appearance of leg length differences due to hemihyperplasia; and stomach wall surgery to treat omphalocele [1] (and umbilical hernia, if it doesn't go away on its own).

Your provider may also recommend genetic counseling [1] for you and your family to help you learn more about your child's condition.

When should my child see their healthcare provider?

You and your child will work with a team of healthcare providers to help manage your child's condition. Your child will need regular check-ups so their providers can monitor their symptoms. Alert your child's provider about any new or worsening symptoms.

All children with BWS have a higher risk of developing childhood cancers. They'll need routine cancer screenings so their healthcare provider can find and treat cancer before it spreads [1].

What's the prognosis for a child with BWS?

Beckwith-Wiedemann syndrome is a complex condition that can affect your child in many ways. The prognosis for your child depends on many factors, including which body parts are affected, how severe their symptoms are, time of diagnosis, and whether tumors develop [1].

Early diagnosis and treatment, along with routine cancer screenings, can lead to the best outcome. Most children who develop Beckwith-Wiedemann syndrome have a normal life expectancy [1].

What's the bottom line?

Beckwith-Wiedemann syndrome is a rare overgrowth disorder that makes most babies larger at birth and may bring features like an enlarged tongue, low newborn blood sugar, and a higher risk of certain childhood cancers. There's no cure, but the picture is far from bleak: growth slows by age 8 to average adult height, treatments correct physical differences and relieve symptoms, routine cancer screenings catch problems early, and most children have a normal life expectancy [1]. If your child has BWS, keep every check-up, act fast on new or worsening symptoms, and lean on the care team — and genetic counseling — to understand what your child's specific situation means and how to help them thrive.

Conclusion and what to do next

If your child has Beckwith-Wiedemann syndrome, work with the full care team: keep regular check-ups, alert your provider to any new or worsening symptoms, and make sure routine cancer screenings happen so cancers can be found and treated before they spread. Ask your provider what medical challenges your child may face — they'll have insight into your child's specific situation. Explore tongue, feeding, sleep, blood sugar, kidney, and surgery options as your child's needs develop, and consider genetic counseling for the family. While BWS can't be cured, medical treatments can help resolve most of your child's symptoms, and most children grow to average adult height and live a normal lifespan [1].

Explore Rinnit.com's library of clear, practical health guides — from genetic conditions and rare diseases to childhood cancer screening, enlarged tongue, and low blood sugar in newborns.

Frequently asked questions

What is Beckwith-Wiedemann syndrome?

BWS is a rare genetic overgrowth disorder (also called Beckwith-Wiedemann spectrum) that affects a child's growth and can involve many body parts. Most babies with BWS are larger than normal at birth.

Why is it called a "spectrum"?

Because symptoms and their severity vary widely. A child may have only one or many of its characteristics.

What are the main characteristics?

Omphalocele (organs outside the belly), macroglossia (large tongue), birth weight above the 95th percentile, enlarged liver, kidney abnormalities, newborn hypoglycemia, hemihyperplasia (one larger body side), earlobe creases, and umbilical hernia.

What is the cancer risk?

About 7.4% overall, with almost all of the risk between birth and age 8. Cancers include Wilms tumor, hepatoblastoma, neuroblastoma, rhabdomyosarcoma, and adrenocortical carcinoma.

How is the cancer risk managed?

Through routine cancer screenings so a provider can find and treat cancer before it spreads.

What causes BWS?

Mostly epigenetic changes on chromosome 11 (region 11p15.5) that affect growth genes through genomic imprinting. About 85% of cases happen randomly, 10–15% are inherited from a parent, and 14–20% have unknown causes.

Is BWS inherited?

Usually not — about 85% of children have no biological family history. When it runs in families, one parent passes down the genetic change.

Are there risk factors?

Assisted reproductive technology (IVF, ICSI) may raise the risk, though more research is needed. BWS is also more common in twin pregnancies.

Can it be diagnosed before birth?

Yes. Prenatal ultrasound can detect features like an enlarged kidney, placenta, or fetus, extra amniotic fluid, macroglossia, or omphalocele, and amniocentesis or chorionic villus sampling can confirm the diagnosis.

How is it treated?

There's no cure, but treatments include CPAP for sleep apnea, specialized feeding support, speech therapy, tongue reduction surgery, IV glucose and medications for hypoglycemia, cardiac/GI/kidney treatments, orthotics or surgery for leg length differences, and stomach wall surgery for omphalocele.

What is the long-term outlook?

Most children reach average adult height (growth slows by age 8) and have a normal life expectancy. Early diagnosis, treatment, and routine cancer screenings lead to the best outcome.

What complications can occur?

Preterm labor; breathing and feeding difficulties, hypoglycemia, and cardiomyopathy after birth; and kidney deposits, cysts, stones, cognitive impairment, male infertility, scoliosis, speech issues, and urinary tract infections from childhood through adulthood.

Will my child be taller than other children?

Some children with BWS are taller than their peers, but growth should slow down by age 8 and they should reach average height in adulthood.

Who manages my child's care?

A team of healthcare providers and specialists, since BWS can affect many body parts. Regular check-ups and cancer screenings are essential.

Should our family get genetic counseling?

Yes — providers may recommend genetic counseling for you and your family to learn more about the condition and your specific situation.

The information in this article is for general informational purposes only and is not intended as professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here.

References

1. Cleveland Clinic. Beckwith-Wiedemann Syndrome. Cleveland Clinic. Updated October 20, 2025. https://my.clevelandclinic.org/health/diseases/21993-beckwith-wiedemann-syndrome

2. Mussa A, et al. Cancer Risk in Beckwith-Wiedemann Syndrome: A Systematic Review and Meta-Analysis Outlining a Novel (Epi)Genotype Specific Histotype Targeted Screening Protocol. J Pediatr. 2016;176:142-149.e1. PMID 27372391. https://doi.org/10.1016/j.jpeds.2016.05.038

3. Mussa A, et al. Assisted Reproductive Techniques and Risk of Beckwith-Wiedemann Syndrome. Pediatrics. 2017;140(1):e20164311. PMID 28634246. https://doi.org/10.1542/peds.2016-4311

4. Ye M, et al. Imprinting disorders in children conceived with assisted reproductive technology in Sweden. Fertil Steril. 2024;122(4):706-714. PMID 38825304. https://doi.org/10.1016/j.fertnstert.2024.05.168

5. Brioude F, et al. Expert consensus document: Clinical and molecular diagnosis, screening and management of Beckwith-Wiedemann syndrome: an international consensus statement. Nat Rev Endocrinol. 2018;14(4):229-249. PMID 29377879. https://doi.org/10.1038/nrendo.2017.166

6. Wang KH, et al. Diagnosis and Management of Beckwith-Wiedemann Syndrome. Front Pediatr. 2020;7:562. PMID 32039119. https://doi.org/10.3389/fped.2019.00562

7. Daley SF, et al. Beckwith-Wiedemann Syndrome. StatPearls. Updated January 7, 2024. https://www.ncbi.nlm.nih.gov/books/NBK558993/

8. Shuman C, et al. Beckwith-Wiedemann Syndrome. GeneReviews®. Revised September 21, 2023. https://www.ncbi.nlm.nih.gov/books/NBK1394/

9. National Library of Medicine. Beckwith-Wiedemann syndrome. MedlinePlus Genetics. Updated December 3, 2021. https://medlineplus.gov/genetics/condition/beckwith-wiedemann-syndrome/

10. National Organization for Rare Disorders. Beckwith-Wiedemann Syndrome. NORD. Updated August 8, 2023. https://rarediseases.org/rare-diseases/beckwith-wiedemann-syndrome/