Four Ways to Repair Spina Bifida Before Birth — and Why None of Them Is Simply "Best"

What new research from 2025 and 2026 tells families weighing surgery during pregnancy against surgery after their baby is born

Surgery to close a baby's spina bifida before birth is no longer a single operation. There are now four ways to do it, and each protects something different — the mother's womb, the length of the pregnancy, or the child's chance of walking and of avoiding a brain shunt. No approach came out ahead overall, so the right choice depends on what a family most wants to protect.

Four studies published between June 2025 and January 2026 make that picture clearer than it has ever been. The first pooled the results of 78 earlier studies from 28 surgical centres to produce a single set of numbers for every approach [1]. The second fed those numbers into a computer model that followed 100,000 simulated pregnancies across the whole lifetime of both mother and child [2]. The third surveyed fetal-surgery centres around the world to find out what they actually do [3]. The fourth described the first 25 operations at a public hospital in São Paulo, Brazil [4].

What spina bifida is, and why timing matters

Spina bifida happens very early in pregnancy, in the first month, when the tube of tissue that becomes the spinal cord fails to close completely. In the open form, a section of spinal cord is left exposed through a gap in the back. Two things then follow. The exposed nerves are damaged by contact with the fluid inside the womb, month after month. And the constant leak of spinal fluid pulls the base of the brain downward into the top of the spinal canal, which blocks the normal circulation of fluid and causes hydrocephalus — a build-up of fluid inside the brain [5].

That is why timing became the central question. It is a common condition on a global scale, and it is far more common in parts of the world where women do not have reliable access to folic acid before and during early pregnancy — the single most effective way to prevent it in the first place [6], [7]. But once a baby has it, prevention is no longer the question. The question becomes whether closing the gap during pregnancy can stop some of the damage that would otherwise continue for months.

How families used to face this decision

For most of the past several decades, the answer was simple because there was only one option. A baby with spina bifida was delivered, and a surgeon closed the back in the first two or three days of life. Families were told to expect that their child would probably need a shunt — a thin tube placed to drain fluid from the brain — and that walking might require braces, a walker, or a wheelchair. Nothing about the pregnancy itself changed. Whatever damage the exposed spinal cord sustained before birth was simply accepted as unavoidable.

That changed in 2011, when a large American trial called the Management of Myelomeningocele Study (MOMS) compared surgery during pregnancy with the usual surgery after birth. It was carried out at fetal-surgery centres in the United States, and only U.S. residents could enrol. The results were striking enough that the trial was stopped early: children operated on before birth needed a shunt far less often, and by age two and a half they were roughly twice as likely to be walking independently as children operated on after birth [8], [9]. Follow-up when those children reached school age found that the walking and independence advantages lasted, though there was no difference in thinking and learning ability between the two groups [10], [11].

But there was a cost, and it fell on the mother. The original operation required a large cut into the wall of the womb while the baby was still inside. That cut never fully returns to normal. It means the baby must be delivered by caesarean section, and so must every baby in every future pregnancy. It also raises the risk of the womb tearing along that scar later on. Over the following decade, surgeons developed smaller and gentler ways of reaching the baby, hoping to keep the benefits for the child while protecting the mother [12], [13].

The four operations, and what each one trades away

The four prenatal approaches differ mainly in how large an opening is made in the womb. The original method uses a cut of about six to eight centimetres. A "minihysterotomy" uses a smaller one, roughly two and a half to three and a half centimetres. Two "fetoscopic" methods use narrow ports and a camera instead of an open cut — one reaching the womb through an abdominal incision first, the other going through the skin directly.

Pooling all the published results, the researchers found that no mother died after any of these operations [1]. But the risks that remained were distributed unevenly. Early breaking of the waters happened in about a third of pregnancies after the open operations and after the camera-through-the-abdomen method — and in 80% after the fully through-the-skin method. Birth before 32 weeks followed the same pattern: 12 to 15% after the open approaches, 13% after one camera method, and 33% after the other. Meanwhile, the scar problems went the opposite way. Partial separation of the womb's scar happened in about 5 to 7% of the open operations and in none of the camera-based ones. And for mothers who went on to have another pregnancy after the original large-incision operation, about 9% experienced a tear in the womb — several times higher than after a standard caesarean section [1].

For the children, the picture reversed again. A shunt was needed within the first year by 17 to 46% of babies operated on before birth, depending on the method, compared with 81% of those operated on after birth. Walking with or without a device by age two and a half ranged from 52% to 81% in the prenatal groups, against 57% in the postnatal group [1]. In other words, the more the surgeons protected the mother's womb, the more they tended to shorten the pregnancy — and prematurity brings its own problems for a newborn.

What a computer model concluded

Because no trial has ever compared these operations head to head, one research group built a model to do it indirectly. It followed 100,000 simulated pregnancies from the moment of surgery through the entire lifetimes of mother and child, adding up not just years lived but years lived in good health [2].

The result was a near-tie. Open surgery and camera-based surgery produced almost exactly the same total — about 1.7 extra healthy years per mother-and-child pair compared with surgery after birth. When the model was run many times with the numbers varied within their realistic ranges, camera-based surgery came out best 51% of the time and open surgery 49% of the time. Surgery after birth came out best in less than one run in three hundred. Camera-based surgery pulled slightly ahead on total years lived, because the model produced fewer maternal deaths and no womb scar separations in that group [2].

The honest reading of that result is not that one operation wins. It is that the difference between the two prenatal approaches is smaller than the uncertainty in the numbers used to compare them. What matters more, most likely, is the experience of the team doing the operation.

What centres around the world are actually doing

A survey of fetal-surgery centres in 2024 found that the original open operation is still the most commonly offered, but that nearly half of centres now offer more than one approach [3]. It also found that the strict eligibility rules used in the original trial have loosened considerably: about 42% of centres will operate later in pregnancy than the trial allowed, and about 64% will accept mothers with a higher body weight than the trial permitted. When asked what decides the choice of operation, centres most often named the type of the baby's spinal lesion — but nearly half also named whether the mother hopes to have more children in the future, and nearly half named the mother's own stated preference [3].

That last point is worth pausing on. A family's plans for future pregnancies are now, in practice, one of the main things that determines which operation is offered.

Bringing the operation to more families

The Brazilian study describes the first 25 fetal spina bifida operations at a public hospital in São Paulo, performed between 2019 and 2023 [4]. The team deliberately relaxed the original trial's rules to fit their setting, where diagnosis and referral often come later. Babies were born on average at 34.3 weeks — almost exactly the same as in the original trial. Waters broke early in 32% of pregnancies and 40% were born preterm. There were no womb ruptures, no emergency hysterectomies, and no maternal deaths. Babies were in good condition at birth, with typical Apgar scores of 8 and 9, and although 44% weighed less than 2,500 g, careful measurement against international growth standards showed this reflected early birth rather than poor growth in the womb [4], [14].

The point of that study is not its size. It is the demonstration that a fetal surgery programme can be built inside a public health system — which matters most in exactly the places where spina bifida is most common.

What this means for your family, and what comes next

If you are facing this decision, three things are worth carrying into the conversation with your team. The strongest and most consistent finding across all of this research is that surgery before birth substantially reduces the chance your child will need a brain shunt. The choice between the different prenatal methods is a choice about which risk you would rather take — a shorter pregnancy, or a scar on the womb that affects future pregnancies. And because the measured differences between methods are small, the experience of the centre performing the operation is a reasonable thing to weigh heavily.

Researchers are now working on the questions these studies could not answer: what happens in later pregnancies for mothers who had the camera-based operations, how children who were repaired before birth are doing as teenagers and adults, and whether the relaxed eligibility rules many centres now use are as safe as the original ones. Until those answers arrive, the most useful thing this research offers families is not a single recommendation, but an honest map of the trade-offs.

References

  1. Kunpalin Y, Karadjole VS, Medeiros ESB, Domínguez-Moreno M, Sichitiu J, Abbasi N, et al. Benefits and complications of fetal and postnatal surgery for open spina bifida: systematic review and proportional meta-analysis. Ultrasound in Obstetrics & Gynecology. 2025;66(2):135–146. doi:10.1002/uog.29240 ↩
  2. Kunpalin Y, Sahakyan Y, Sander B, Snelgrove JW, Raghuram K, Kulkarni AV, et al. Comparison of open fetal, fetoscopic and postnatal surgical repair for open spina bifida: decision analysis. Ultrasound in Obstetrics & Gynecology. 2025;66(4):433–442. doi:10.1002/uog.29289 ↩
  3. Keil C, Wiora N, Krispin E, Windhorst A, Axt-Fliedner R, Bedei I. Evolving practices in prenatal open spinal dysraphism: a global survey of selection criteria, surgical techniques, and diagnostic trends. Prenatal Diagnosis. 2026;46(1):75–83. doi:10.1002/pd.70031 ↩
  4. Schwach I, Callado GY, Herbst SRS, Cardeal DD, Toita MH, Tedesco GD, et al. Fetal surgery for myelomeningocele: initial results of a tertiary public hospital. Revista Brasileira de Ginecologia e Obstetrícia. 2025;47:e-rbgo81. doi:10.61622/rbgo/2025rbgo81 ↩
  5. Copp AJ, Adzick NS, Chitty LS, Fletcher JM, Holmbeck GN, Shaw GM. Spina bifida. Nature Reviews Disease Primers. 2015;1:15007. doi:10.1038/nrdp.2015.7 ↩
  6. Blencowe H, Kancherla V, Moorthie S, Darlison MW, Modell B. Estimates of global and regional prevalence of neural tube defects for 2015: a systematic analysis. Annals of the New York Academy of Sciences. 2018;1414(1):31–46. doi:10.1111/nyas.13548 ↩
  7. De-Regil LM, Peña-Rosas JP, Fernández-Gaxiola AC, Rayco-Solon P. Effects and safety of periconceptional oral folate supplementation for preventing birth defects. Cochrane Database of Systematic Reviews. 2015;(12):CD007950. doi:10.1002/14651858.CD007950.pub3 ↩
  8. Adzick NS, Thom EA, Spong CY, Brock JW, Burrows PK, Johnson MP, et al. A randomized trial of prenatal versus postnatal repair of myelomeningocele. New England Journal of Medicine. 2011;364(11):993–1004. doi:10.1056/NEJMoa1014379 ↩
  9. Farmer DL, Thom EA, Brock JW, Burrows PK, Johnson MP, Howell LJ, et al. The Management of Myelomeningocele Study: full cohort 30-month pediatric outcomes. American Journal of Obstetrics and Gynecology. 2018;218(2):256.e1–256.e13. doi:10.1016/j.ajog.2017.12.001 ↩
  10. Houtrow AJ, Thom EA, Fletcher JM, Burrows PK, Adzick NS, Thomas NH, et al. Prenatal repair of myelomeningocele and school-age functional outcomes. Pediatrics. 2020;145(2):e20191544. doi:10.1542/peds.2019-1544 ↩
  11. Houtrow AJ, MacPherson C, Jackson-Coty J, Rivera M, Flynn L, Burrows PK, et al. Prenatal repair and physical functioning among children with myelomeningocele: a secondary analysis of a randomized clinical trial. JAMA Pediatrics. 2021;175(4):e205674. doi:10.1001/jamapediatrics.2020.5674 ↩
  12. Moldenhauer JS, Adzick NS. Fetal surgery for myelomeningocele: after the Management of Myelomeningocele Study (MOMS). Seminars in Fetal and Neonatal Medicine. 2017;22(6):360–366. doi:10.1016/j.siny.2017.08.004 ↩
  13. Sanz Cortes M, Chmait RH, Lapa DA, Belfort MA, Carreras E, Miller JL, et al. Experience of 300 cases of prenatal fetoscopic open spina bifida repair: report of the International Fetoscopic Neural Tube Defect Repair Consortium. American Journal of Obstetrics and Gynecology. 2021;225(6):678.e1–678.e11. doi:10.1016/j.ajog.2021.05.044 ↩
  14. Villar J, Cheikh Ismail L, Victora CG, Ohuma EO, Bertino E, Altman DG, et al. International standards for newborn weight, length, and head circumference by gestational age and sex: the Newborn Cross-Sectional Study of the INTERGROWTH-21st Project. The Lancet. 2014;384(9946):857–868. doi:10.1016/S0140-6736(14)60932-660932-6) ↩