Open spina bifida is one of the physical conditions that the NHS 20-week screening scan specifically looks for when checking a baby’s development during pregnancy, and most cases can be identified before birth.

However, spina bifida can sometimes be missed on an ultrasound as factors such as the baby's position can make it difficult to obtain clear images.

Not every missed diagnosis means that medical negligence has occurred. However, there may be grounds for a medical negligence claim if signs that should reasonably have been identified were missed, an incomplete scan was not appropriately followed up, or the pregnant mother was not referred for further assessment when they should have been.

In this guide, Kimberly Peet, expert clinical negligence solicitor at JMW, explains what hospitals should look for during the 20-week scan, why spina bifida can sometimes go undetected and what should happen when a potential abnormality is found. She also explains how parents can pursue a wrongful birth claim if medical negligence denied them information they should have received during pregnancy.

What Is Spina Bifida?

Spina bifida is a type of neural tube birth defect. It develops very early in pregnancy when the neural tube, which eventually develops into the baby’s brain tissue, spinal cord and surrounding structures, does not close completely.

There are different types of spina bifida, and their effects can vary significantly.

• Spina bifida occulta is generally the mildest form. There is a gap between some of the spinal bones, but the spinal cord and nerves are usually not exposed. Many people with spina bifida occulta have no symptoms and may not know they have it unless it is discovered incidentally through an X-ray or MRI later in life.
• Meningocele is a rare form of spina bifida in which a sac containing membranes and cerebrospinal fluid protrudes through an opening in the spine.
• Myelomeningocele is the most severe form and is usually what is meant by open spina bifida, also known as spina bifida aperta. Part of the spinal cord and nerves develop outside the spinal canal, potentially causing significant nerve damage.

The symptoms of spina bifida depend on the type and location of the neural tube defect. Some people have mild symptoms, while more severe cases can affect movement, sensation, bladder and bowel function and independence.

Folic acid plays an important role in reducing the risk of neural tube defects, which is why folic acid supplementation is recommended before pregnancy and during the early stages of pregnancy. However, spina bifida can still occur even where recommended folic acid guidance has been followed.

Should Spina Bifida Be Detected at the 20-Week Scan?

The NHS 20-week screening scan, sometimes called the anomaly scan, is usually offered between 18 and 21 weeks of pregnancy. Open spina bifida is one of the conditions the 20-week scan specifically screens for.

The sonographer examines the baby's development, including the fetal spine and structures within the brain. Open spina bifida can produce identifiable changes in both areas.

However, as with all screening, it is not 100 per cent accurate. A scan cannot guarantee that every condition will be identified. Some abnormalities are not capable of being detected during a scan. Image quality may also be affected by factors such as uterine fibroids or higher BMI. Re-scanning should be offered where the quality of the imaging is compromised. A second opinion should be sought if an unexpected structural development is suspected and the image quality is sub-optimal.   

If spina bifida was not identified during pregnancy, the question is not simply whether it was present at the time of the scan. The question in a medical negligence investigation is whether the signs were reasonably identifiable and whether the sonographer and hospital responded appropriately to the information available.

What Does a Sonographer Look for During the 20-Week Scan?

During the scan, the sonographer examines the baby's spine and checks its development and appearance. They also assess other parts of the baby's anatomy.

Open spina bifida can affect structures beyond the spinal cord. Changes in the appearance of the brain and skull may provide additional signs that further assessment is needed. Some babies with open spina bifida can also develop hydrocephalus, where cerebrospinal fluid builds up within the brain.

The 20-week scan also checks for other specified physical conditions. These include serious abnormalities affecting brain structure and certain heart defects.

Different conditions have different detection rates. The fact that the scan screens for a condition does not mean it will be identified in every affected pregnancy.

What Are Hospitals Expected to Do During the 20-Week Scan?

Hospitals should follow the appropriate screening pathway when carrying out the 20-week scan. This includes examining the required parts of the baby's anatomy and obtaining suitable views where possible. 

The sonographer should:

• Carry out all the required structural checks to an appropriate standard
• Obtain and store the necessary ultrasound images 
• Recognise and document abnormalities that are reasonably identifiable
• Explain relevant findings to the parent
• Arrange for a second scan if image quality is poor. 
• Make a specialist referral when structural abnormalities are seen or suspected. 

Sometimes the sonographer cannot obtain all of the necessary views. Poor fetal positioning, for example, can make it difficult to see the fetal spine clearly.

An unclear view does not necessarily indicate anything is wrong with the baby. However, where the required checks cannot be completed, the hospital should follow the appropriate pathway rather than treating an incomplete examination as confirmation that everything is normal.

What Should Happen If Spina Bifida Is Suspected?

If the 20-week scan identifies or raises concerns about a possible neural tube defect, the mother and baby should receive appropriate further assessment.

Depending on the findings, this can include a more detailed ultrasound and referral to a fetal medicine specialist. Further investigations may be required to establish a diagnosis of spina bifida and understand its likely effects.

Parents should receive clear and balanced information about what has been identified, what remains uncertain and what further testing or assessment is available. Where a diagnosis is confirmed, the medical team should explain the condition, the possible implications and the options available for the pregnancy.

For some cases of open spina bifida, fetal surgery may be considered as a treatment option before birth. However, it is only suitable in particular circumstances and requires detailed assessment by a specialist team

Not every baby with spina bifida will be suitable for prenatal repair, and parents should receive appropriate information about the potential risks when considering their options.

Why Can Spina Bifida Be Missed on Ultrasound?

There are several reasons a diagnosis of spina bifida may not be made during pregnancy. Not all involve negligent care.

The form of spina bifida is difficult to detect

Open spina bifida generally produces more identifiable prenatal signs than closed spina bifida, and is the form that is checked for on the 20 week scan.

Clear images could not be obtained

The baby's position may obscure the spine. Other factors can also affect ultrasound clarity.

Where the sonographer cannot complete the necessary checks, the important question is whether appropriate steps were taken afterwards.

Visible abnormalities were overlooked

In some cases, the necessary images may have been obtained but an abnormality was not recognised.

An independent expert can review the original scan images to establish whether a reasonably competent sonographer should have identified the finding at the time.

Findings were misinterpreted or misreported

A finding may be recognised but incorrectly interpreted, documented or communicated. This could prevent the parent from being referred for the specialist assessment they should have received.

Further assessment was not arranged

Sometimes the concern is not the original scan itself. An abnormal or uncertain finding may have been identified correctly, but the hospital then failed to arrange an appropriate repeat scan, specialist referral or further investigation.

How Late Can Spina Bifida Be Diagnosed?

This depends substantially on the type of spina bifida. Open spina bifida is usually capable of being identified antenatally and is specifically targeted during the mid-pregnancy anomaly scan.

Spina bifida occulta can sometimes remain undiagnosed into childhood or adulthood. It may be discovered when imaging such as an X-ray or MRI is carried out for another reason.

Where symptoms do occur, signs in a child can include muscle weakness or changes in leg movement, bladder symptoms or bowel symptoms. Certain skin changes over the lower spine can also sometimes prompt further investigation.

A tethered spinal cord can also cause neurological problems as a child grows. Where a tethered cord or another spinal cord issue is suspected, doctors may use MRI or other appropriate imaging to investigate.

A late diagnosis does not automatically mean that the condition should have been identified during pregnancy. This will depend on the form of spina bifida and what was reasonably detectable at the time.

Does Missing Spina Bifida Mean the Hospital Was Negligent?

Not necessarily. No antenatal screening programme can identify every condition, and some types of spina bifida are much harder to detect than others. The fact that a baby was diagnosed with spina bifida after birth is therefore not enough on its own to establish medical negligence.

There may be grounds to investigate if, for example:

• Required views of the baby's spine or brain were not obtained and appropriate follow-up was not arranged
• Signs of open spina bifida that should reasonably have been visible were overlooked
• An abnormality was incorrectly interpreted or reported as normal
• Significant findings were not communicated to the parents
• An appropriate repeat scan was not arranged
• A referral to fetal medicine specialists was delayed or not made
• Parents did not receive appropriate information about a suspected or confirmed diagnosis

Independent medical evidence will usually be required to establish what a reasonably competent sonographer, doctor or hospital should have done.

Read our medical gaslighting blog post to learn more about how failures to act on important findings from medical appointments can have serious consequences.

When Can Missed Spina Bifida Lead to a Wrongful Birth Claim?

A wrongful birth claim may be possible where medical negligence during pregnancy meant parents were not properly informed about their baby's health and this affected the decision they would have made with the pregnancy. This is consistent with JMW's established approach to wrongful birth claims.

For example, suppose signs of open spina bifida were visible at the 20-week scan but were negligently missed. Had they been identified, the parent might have been referred to fetal medicine, received a diagnosis and been given information about the condition and their options.

To make a successful medical negligence claim, it is generally necessary to establish both breach of duty and causation.

Breach of duty means showing that the care provided fell below a reasonable standard. Causation means establishing what difference that failure made. In a wrongful birth claim, this will require evidence that appropriate care would probably have led to the diagnosis being made and communicated to the parents in time, and that they would have decided to terminate the pregnancy as a result. 

A wrongful birth claim is not a judgement on a child's life. It does not change the love the parents have for their child, it recognises that they should have received accurate information during pregnancy. The claim concerns the loss of informed choice and the additional financial consequences that may follow from proceeding with the pregnancy and the birth of their child. 

What Evidence Is Needed to Investigate a Missed Diagnosis?

The original ultrasound evidence can be particularly important in a claim involving a missed spina bifida diagnosis.

We may obtain:

• Ultrasound images from the 20-week scan
• The sonographer's scan report
• Earlier and later prenatal ultrasound records
• Maternity records
• Records of any incomplete or repeat scans
• Fetal medicine records
• Referral documents
• Records of discussions with the parents
• Medical records relating to the child's diagnosis after birth

Independent experts can then review the original images and records.

The purpose is not to look at the scan with hindsight. An expert assesses what should reasonably have been identified based on the images and information available to the healthcare professionals at the time.

What Is Compensation for in a Spina Bifida Wrongful Birth Claim?

Wrongful birth compensation is intended to address the additional impact and financial needs arising from the child's condition where medical negligence deprived parents of an informed choice in regard to the pregnancy. It is not intended to place a financial value on the child's life.

Depending on the individual circumstances, compensation may take account of additional:

• Care and assistance
• Physiotherapy and occupational therapy
• Specialist medical support
• Mobility aids and wheelchairs
• Bladder and bowel management
• Equipment and assistive technology
• Specialist education
• Adapted transport
• Home adaptations or suitable accommodation
• Relevant parental loss of earnings

Some children with spina bifida may need treatment for associated conditions such as hydrocephalus or support for muscle weakness, mobility difficulties and bladder or bowel problems. Others will have very different needs.

Independent medical, care, therapy, accommodation and other experts can assess these requirements so that the claim reflects the child's circumstances rather than assumptions based on the diagnosis alone. 

JMW's wrongful birth service similarly focuses compensation on additional care, equipment, accommodation, therapy and other needs linked to the child's condition.

How Do You Pursue a Claim if Spina Bifida Was Missed?

You do not need to know exactly why the diagnosis was missed before speaking to a medical negligence solicitor.

The claims process will usually begin with a discussion about what happened during the pregnancy and when your child's spina bifida was eventually diagnosed.

We can then obtain the relevant medical records and original ultrasound images. Independent medical experts can assess whether the 20-week scan and subsequent care met a reasonable standard and whether the condition should probably have been identified.

If the evidence supports a claim, we will also consider what information you would have received with appropriate care and how this would have affected your decisions during pregnancy.

Further independent evidence can then establish your child's additional care, equipment, therapy, accommodation and other long-term needs.

Where appropriate, the claim is then put to the responsible healthcare provider. This may be an NHS trust or a private provider, depending on where the relevant care was provided.

How Long Do You Have to Make a Claim?

There is generally a three-year time limit for starting a medical negligence claim in the court process. This may run from the negligent care or from the date you first knew, or could reasonably have known, that medical negligence may have caused avoidable harm.

In a missed diagnosis case, parents may not realise that something went wrong until after their child's birth, when later investigations reveal what should have been identified during pregnancy. JMW's wrongful birth guidance therefore emphasises that the relevant date depends on the individual circumstances.

Different rules can apply in some situations. Speaking to a solicitor promptly allows the relevant dates to be reviewed and gives the legal team time to obtain ultrasound images, maternity records and expert evidence.