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PubMed This is a summary of 17 peer-reviewed journal articles Updated
Pediatric Neurosurgery · Myelomeningocele

Treatment Strategy: Comparing Fetal and Postnatal Repair

At a Glance

The timing of surgery for myelomeningocele (spina bifida) involves choosing between prenatal (fetal) and postnatal repair. Fetal surgery between 19 and 26 weeks may improve mobility and reduce the need for a brain shunt, but carries risks of preterm birth and uterine scarring for the mother.

When a diagnosis of myelomeningocele (the most severe open form of spina bifida) is confirmed, one of the most significant decisions a family may face is the timing of the surgical repair. Traditionally, babies were operated on shortly after birth (postnatal repair) [1]. However, a landmark study called the MOMS trial (Management of Myelomeningocele Study) changed the landscape of treatment by comparing postnatal surgery with surgery performed while the baby is still in the womb (prenatal or in-utero surgery) [2][1].

The Paradigm Shift: Fetal vs. Postnatal Repair

The MOMS trial established that repairing the spinal defect during pregnancy can protect the developing spinal cord from further damage caused by exposure to amniotic fluid [3]. Neither option is a “cure,” but each has a different set of potential benefits and risks.

Prenatal (In-Utero) Repair

This surgery is typically performed between 19 and 26 weeks of pregnancy [1]. Because many families do not receive a diagnosis until their 20-week anatomy scan, the window to qualify for surgery closes quickly. It is essential to seek an immediate referral to a fetal care center to evaluate your options [2].

  • The Potential Benefits: Research shows that babies who undergo prenatal repair are significantly less likely to need a shunt (a tube to drain fluid from the brain) and are more likely to walk independently compared to those who have surgery after birth [1][4]. It can also “reverse” or improve the Chiari II malformation (the shifting of the brain toward the spinal canal) [2].
  • The Risks: The primary risk is preterm birth, which occurs in the vast majority of fetal surgery cases (averaging around 34 weeks in the MOMS trial) and can lead to its own health challenges for the baby [5][6]. For the mother, risks include uterine thinning or scarring (dehiscence) and the need for a Cesarean section for all future deliveries [7][8].

Postnatal Repair

In this approach, the baby is delivered (often via a planned C-section) and the spinal defect is repaired by a pediatric neurosurgeon within the first 24 to 48 hours of life [9].

  • The Potential Benefits: This avoids the maternal risks of fetal surgery and the high risk of very early preterm birth [2]. It allows the baby to grow to full term in the womb.
  • The Risks: Because the nerves remain exposed to amniotic fluid for the duration of the pregnancy, there is a higher likelihood of nerve damage, a greater need for brain shunts, and a lower probability of independent walking [1][10].

Surgical Techniques: Open vs. Fetoscopic

If prenatal surgery is chosen, there are two main ways it can be performed:

  • Open Hysterotomy: The traditional method used in the MOMS trial, where a surgical incision is made in the mother’s uterus to reach the baby [1].
  • Fetoscopic Repair: A newer, minimally invasive technique where small cameras and instruments are inserted through tiny holes in the uterus [11]. This may reduce some maternal risks, such as uterine scarring, and in some cases, may allow for a vaginal delivery, but it is a complex procedure that is still being refined [12][13].

Am I a Candidate for Fetal Surgery?

Fetal surgery is not an option for every pregnancy. Centers typically follow strict eligibility criteria to ensure safety for both mother and baby [1].

  • Criteria for Fetal Surgery: The baby must have a confirmed myelomeningocele at a specific spinal level (usually between T1 and S1) and show signs of the Chiari II malformation [1][14]. The mother must have a healthy pregnancy otherwise, with no history of certain uterine surgeries or medical conditions that would make surgery unsafe [15][6].
  • Exclusions: Factors like carrying twins, severe chromosomal abnormalities in the baby, or the mother having a high risk of preterm labor usually exclude a family from prenatal surgery [16][17].

Common questions in this guide

When does fetal surgery for spina bifida need to be performed?
Prenatal surgery for myelomeningocele is typically performed between 19 and 26 weeks of pregnancy. Because the window closes quickly after a 20-week anatomy scan, it is important to seek an immediate evaluation at a specialized fetal care center.
What are the benefits of repairing spina bifida before birth?
Babies who undergo prenatal repair are significantly less likely to need a brain shunt to drain fluid and are more likely to walk independently. Prenatal surgery can also improve the Chiari II malformation, which is the shifting of the brain toward the spinal canal.
What are the main risks of in-utero spina bifida surgery?
The primary risk for the baby is preterm birth, which can cause its own health complications. For the mother, risks include uterine scarring and the requirement to deliver via Cesarean section for all future pregnancies.
What is postnatal repair for myelomeningocele?
In postnatal repair, the baby is delivered to full term and the spinal defect is closed by a pediatric neurosurgeon within the first 24 to 48 hours of life. This avoids the maternal risks associated with fetal surgery.
Is every pregnancy eligible for fetal surgery?
Eligibility depends on strict criteria to ensure the safety of both mother and baby. The baby must have a specific level of spinal defect and signs of Chiari II malformation, while the mother must be generally healthy without a high risk for preterm labor or previous uterine surgeries.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on my baby's diagnosis, do we meet the specific criteria used in the MOMS trial for fetal surgery?
  2. 2.What are the success rates and typical complication rates at this specific center for both prenatal and postnatal repairs?
  3. 3.If we choose prenatal surgery, what are the chances that our baby will still require a shunt after birth?
  4. 4.Does this center perform open hysterotomy or fetoscopic repair, and how do you compare the risks of each for my specific situation?
  5. 5.What is the typical 'window' of time we have to make this decision before the gestational age limit?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (17)
  1. 1

    Fetal surgery for spina bifida.

    Dewan MC, Wellons JC

    Journal of neurosurgery. Pediatrics 2019; (24(2)):105-114.

    PMID: 31370010
  2. 2

    Fetal surgery for myelomeningocele: After the Management of Myelomeningocele Study (MOMS).

    Moldenhauer JS, Adzick NS

    Seminars in fetal & neonatal medicine 2017; (22(6)):360-366 doi:10.1016/j.siny.2017.08.004.

    PMID: 29031539
  3. 3

    Open fetal surgery for neural tube defects.

    Moldenhauer JS, Flake AW

    Best practice & research. Clinical obstetrics & gynaecology 2019; (58()):121-132 doi:10.1016/j.bpobgyn.2019.03.004.

    PMID: 31078425
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    Prenatal surgery for myelomeningocele: review of the literature and future directions.

    Heuer GG, Moldenhauer JS, Scott Adzick N

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2017; (33(7)):1149-1155 doi:10.1007/s00381-017-3440-z.

    PMID: 28516217
  5. 5

    Seeking tirelessly for better health and life conditions for the child with myelomeningocele.

    Bonelli MA, Borges AA, Souza ROD, et al.

    Revista latino-americana de enfermagem 2021; (29()):e3428 doi:10.1590/1518-8345.3957.3428.

    PMID: 34037122
  6. 6

    Chorioamniotic membrane separation and preterm premature rupture of membranes complicating in utero myelomeningocele repair.

    Soni S, Moldenhauer JS, Spinner SS, et al.

    American journal of obstetrics and gynecology 2016; (214(5)):647.e1-7.

    PMID: 26692177
  7. 7

    Ultrasound evaluation of uterine scar thickness after open fetal surgery for myelomeningocele.

    Sasaoka AKS, Moron AF, Araujo Júnior E, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2023; (39(3)):655-661 doi:10.1007/s00381-022-05642-0.

    PMID: 35939128
  8. 8

    Subsequent pregnancy outcomes after open maternal-fetal surgery for myelomeningocele.

    Goodnight WH, Bahtiyar O, Bennett KA, et al.

    American journal of obstetrics and gynecology 2019; (220(5)):494.e1-494.e7 doi:10.1016/j.ajog.2019.03.008.

    PMID: 30885769
  9. 9

    Patterns and short term neurosurgical treatment outcomes of neonates with neural tube defects admitted to Felege Hiwot Specialized Hospital, Bahir Dar, Ethiopia.

    Addisu Y, Wassie GT

    BMC pediatrics 2024; (24(1)):350 doi:10.1186/s12887-024-04837-5.

    PMID: 38773409
  10. 10

    Neurologic Outcome Comparison between Fetal Open-, Endoscopic- and Neonatal-Intervention Techniques in Spina Bifida Aperta.

    Sival DA, Patuszka A, Koszutski T, et al.

    Diagnostics (Basel, Switzerland) 2023; (13(2)) doi:10.3390/diagnostics13020251.

    PMID: 36673061
  11. 11

    The Management of Myelomeningocele Study and Beyond: Trends and Innovations in the Management of Myelomeningocele.

    Fogel H, Adapa AR, Teasley DE, Feldstein NA

    World neurosurgery 2025; (199()):123983 doi:10.1016/j.wneu.2025.123983.

    PMID: 40685172
  12. 12

    Safety and Effectiveness of Fetal Myelomeningocele Repair: Case Series Analysis Using an Exteriorized Uterus and a Fetoscopic Approach.

    Miranda ML, Ximenes R, Andrade KC, et al.

    Fetal diagnosis and therapy 2025; (52(5)):521-531 doi:10.1159/000546549.

    PMID: 40435982
  13. 13

    Open and endoscopic fetal myelomeningocele surgeries display similar in-hospital safety profiles in a large, multi-institutional database.

    Mikulski MF, Well A, Beckerman Z, et al.

    American journal of obstetrics & gynecology MFM 2023; (5(3)):100854 doi:10.1016/j.ajogmf.2022.100854.

    PMID: 36587805
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    Fetal Repair of Neural Tube Defects.

    Lee SY, Papanna R, Farmer D, Tsao K

    Clinics in perinatology 2022; (49(4)):835-848 doi:10.1016/j.clp.2022.06.004.

    PMID: 36328602
  15. 15

    The Use of Indomethacin with Complete Amniotic Fluid Replacement and Classic Hysterotomy for the Reduction of Perinatal Complications of Intrauterine Myelomeningocele Repair.

    Zamłyński M, Zamłyński J, Horzelska E, et al.

    Fetal diagnosis and therapy 2019; (46(6)):415-424 doi:10.1159/000496811.

    PMID: 31085918
  16. 16

    Prenatal surgery for myelomeningocele and the need for cerebrospinal fluid shunt placement.

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    Cranial findings detected by second-trimester ultrasound in fetuses with myelomeningocele: a systematic review.

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    PMID: 32926566

This page provides educational information on surgical options for myelomeningocele. It does not replace professional medical advice. Always discuss your specific diagnosis, eligibility, and treatment risks with your maternal-fetal medicine specialist and pediatric neurosurgeon.

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