Gram Research analysis of a 2026 study found that babies with multiple neural tube defects differ from those with a single defect. Small skull openings and spinal problems were more common, severe openings were rarer, and many cases were not diagnosed until a week or more after birth. The study pooled about 149 cases.
Neural tube defects are serious birth defects that affect the brain or spine. Most occur at a single site, but some babies have two or more separate defects along the brain and spinal cord. According to research reviewed by Gram, a 2026 study combined 21 new cases from three medical centers with 128 published cases to look for patterns. The researchers found that these multi-site defects differ from single defects. Small skull openings and spinal problems such as split cord malformations were more common, while severe brain and spinal openings were rarer. Many affected children were not diagnosed until a week or more after birth. Children with multiple defects also tended to have fewer associated health problems and less difficulty with movement and thinking. The causes remain largely unknown, so more research is needed.
Key Statistics
A 2026 study in Birth Defects Research that pooled 21 new cases with 128 published cases found that severe brain openings such as anencephaly were rarer in babies with multiple neural tube defects than in those with a single defect.
Single neural tube defects occur at about 5 in 10,000 births in countries with dietary folic acid fortification, while multiple defects occur much less often, according to a 2026 analysis of 149 cases.
According to research reviewed by Gram, many babies with multiple neural tube defects were not diagnosed until a week or more after birth, based on a 2026 study of 149 cases.
The Quick Take
- What they studied: Researchers wanted to understand babies who are born with more than one neural tube defect, meaning two or more separate problems in the brain or spinal cord with normal tissue between them. They asked how these cases differ from single defects and what patterns they follow.
- Who participated: The study pooled 21 cases from three medical centers with 128 similar cases reported in earlier medical literature, for a total of about 149 cases. The exact ages and backgrounds of all participants were not described in the summary available to us.
- Key finding: Babies with multiple neural tube defects more often had small skull openings and spinal problems, and less often had the most severe brain and spinal openings seen in single defects. Many were not diagnosed until a week or more after birth, and surviving children tended to have fewer movement and thinking difficulties.
- What it means for you: These findings describe how multiple neural tube defects look and when they are often found. They do not offer a way to prevent or treat them. Anyone planning a pregnancy should talk with a doctor about standard steps, such as getting enough folic acid, which is known to lower the risk of neural tube defects in general.
The Research Details
This study looked back at medical records of 21 babies with multiple neural tube defects from three medical centers. Neural tube defects develop early in pregnancy, when the tissue that becomes the brain and spinal cord folds and closes. The researchers recorded the location, type, and timing of each defect.
To get a larger picture, the team also collected 128 similar cases that had already been published in medical journals. Combining the two groups allowed them to compare multiple defects with the well-known patterns of single defects.
The researchers grouped defects by when in pregnancy they likely formed. Some happen during the initial folding of the neural tube, while others occur during earlier or later steps of development. This helped them connect each pattern to a likely stage of development.
Looking at many cases together helps reveal patterns that a single hospital could miss, especially for a rare condition. Because multiple neural tube defects are uncommon, combining records from several centers and past reports gives a more reliable view of what these cases typically look like.
Comparing these cases with single defects also helps doctors understand whether the causes may be different. This can guide future questions about why these defects happen.
The study combines new hospital records with published cases, which can be useful for rare conditions. However, published case reports tend to describe unusual or interesting cases, so the combined group may not represent all babies with these defects. Because the study looked back at records rather than following babies from the start of pregnancy, it cannot prove what causes these patterns. The summary also does not state the exact sample size of the hospital group, the time period studied, or whether all 149 cases were checked in the same way.
What the Results Show
The main finding is that multiple neural tube defects look different from single ones. Severe defects that often appear with single defects, such as anencephaly (a condition where most of the brain does not form) and open spinal defects, were less common. In contrast, small skull openings called cephaloceles and spinal problems such as split cord malformations and fatty growths called lipomas were seen more often.
The researchers also described common combinations. One frequent pattern was a skull defect paired with a spinal problem. Another was two or more separate spinal defects. These repeating patterns suggest that the defects may follow shared development pathways rather than occurring at random.
Timing was another important result. Some babies were identified during pregnancy or soon after birth, but many were not found until a week or more after delivery. This means some families may not learn about the full set of defects right away, which can affect early care.
The study also found that babies with multiple defects had fewer other health problems linked to their condition. Surviving children tended to have less difficulty with movement and thinking compared with what is often seen in single defects, though the summary does not provide exact percentages.
The researchers found that most multiple defects appear to start from problems at specific stages of early development. Some problems occur before the neural tube closes, some occur during the closing, and some occur after closing. Problems with a later step called secondary neurulation appeared rare. This detail may help specialists understand which steps are most often disrupted.
The team also noted that few clues have been found about genetic or environmental causes. This is an important gap, because knowing the cause could eventually help with prevention.
Single neural tube defects are among the most common serious birth defects of the nervous system, occurring at about 5 in 10,000 births in countries that add folic acid to flour or other foods. Multiple defects are much less common. This study adds to earlier work by describing how multiple defects differ from single defects in location, type, and timing of diagnosis. Its main contribution is pulling together many scattered cases into one picture, since earlier reports were usually small.
The study is based on a small hospital group of 21 cases plus published reports, so results may not apply to all babies with multiple defects. Published cases are often unusual, which can skew the picture. Because the research looked back at past records, it cannot show cause and effect or explain why these patterns occur. The summary also does not describe how cases were diagnosed in every report or whether all children were followed for the same length of time. Finally, the causes of these defects remain unclear, so the study cannot recommend specific ways to prevent them.
The Bottom Line
Doctors and families should be aware that babies with one neural tube defect may have others, and that these can be missed until after birth. Confidence in this pattern is moderate, because it comes from a combined set of cases rather than a large controlled study. Standard prevention, such as getting enough folic acid before and during early pregnancy, is well supported for neural tube defects in general. Confidence that this helps specifically with multiple defects is lower, since the study did not test it.
Parents, pregnant people, healthcare providers, and researchers who work with birth defects may find this useful. People who are not pregnant and do not have a family history of these conditions will likely find the details less directly relevant. Anyone with questions about their own pregnancy or a child’s health should speak with a doctor rather than rely on this summary.
This research is a description of patterns rather than a treatment, so it will not change anyone’s health directly in the short term. Over the coming years, it may help doctors recognize multiple defects sooner and guide further studies into causes. Any real change in prevention or care would likely take many years of additional research.
Frequently Asked Questions
What is a neural tube defect?
A neural tube defect is a birth defect that affects the brain or spinal cord, which form from a tube of tissue early in pregnancy. Single defects occur at about 5 in 10,000 births in countries with folic acid fortification, according to the research reviewed by Gram.
How are multiple neural tube defects different from single ones?
Multiple neural tube defects more often involve small skull openings and spinal problems like split cord malformations. Severe defects such as anencephaly were less common. A 2026 study of 149 cases also found fewer associated health problems in surviving children.
Can folic acid prevent multiple neural tube defects?
Folic acid is well established for reducing the risk of neural tube defects in general. This study did not test folic acid for multiple defects specifically, so it cannot confirm that folic acid prevents them. Anyone planning a pregnancy should ask a doctor about folic acid.
When are multiple neural tube defects usually found?
Some are found during pregnancy or in the first days after birth, but many are not identified until a week or more after delivery. The 2026 study of 149 cases highlights this delay, which can postpone follow-up care for families.
Want to Apply This Research?
- For users planning or tracking a pregnancy, log daily folic acid intake from supplements and fortified foods, aiming for the amount a doctor recommends. Also log the date of each prenatal visit and any ultrasound results so that changes in findings are easy to review with a clinician.
- Encourage users to set a daily reminder to take a prenatal vitamin or folic acid supplement if they could become pregnant. The app can also suggest eating folate-rich foods such as leafy greens, beans, and fortified cereals, and remind users to schedule a pre-pregnancy visit with a doctor.
- Over time, users can track folic acid intake, prenatal appointments, and any questions to bring to their care team. For families with a child who has a neural tube defect, the app can store medical records, follow-up appointments, and developmental milestones so that providers have a clear timeline. Any health concern should be discussed with a qualified clinician.
This article summarizes a research study for general information only and is not medical advice. The findings describe patterns in a small number of cases and do not show what causes these birth defects or how to prevent them. Anyone who is pregnant, planning a pregnancy, or concerned about a child’s health should talk with a qualified healthcare provider.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.