Illustration of minimally invasive fetal surgery with Doppler waves visualizing blood flow in the womb

Fetal Surgery Breakthrough: Minimally Invasive Techniques Improve Outcomes

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Mira Elwood in Health & Wellness December 2025 • 4 min read.

"Explore how fetoscopic surgery is revolutionizing the treatment of myelomeningocele, offering new hope for babies and their families."


Myelomeningocele (MMC), a complex birth defect affecting the spinal cord, presents significant challenges for newborns, often leading to impaired mobility, bowel and bladder dysfunction, and other neurological issues. Traditional approaches to MMC involved postnatal surgery, aiming to correct the defect after birth. However, this method often left irreversible damage, underscoring the need for earlier intervention.

Groundbreaking research has demonstrated that prenatal repair of MMC can lead to improved neurodevelopmental outcomes compared to postnatal surgery. One notable study, the Management of Myelomeningocele Study, highlighted the benefits of intervening before birth. However, open fetal surgery, while effective, carries risks for the mother, including potential complications at delivery.

To mitigate these maternal risks, minimally invasive fetoscopic techniques have emerged as a promising alternative. This innovative approach involves performing surgery on the fetus through small incisions in the mother's abdomen, reducing the need for large incisions and minimizing trauma. As fetoscopic techniques evolve, ongoing research focuses on understanding the subtle changes in fetal physiology during these procedures, ensuring the safety and well-being of both mother and child.

Understanding Doppler Changes During Fetoscopic MMC Repair

Illustration of minimally invasive fetal surgery with Doppler waves visualizing blood flow in the womb

A recent study investigated the real-time changes in fetal blood flow during fetoscopic MMC repair. Because traditional open MMC repair often obscures the ability to monitor fetal blood flow due to loss of amniotic fluid, the study focused on the umbilical artery (UA) and ductus venosus (DV) using Doppler ultrasound during fetoscopic procedures.

The study, conducted at a major medical center between 2014 and 2017, analyzed ultrasound images taken during 35 fetoscopic MMC repairs. Researchers examined the Doppler parameters of the UA and DV, correlating these changes with specific stages of the surgery. The goal was to identify patterns and understand how the procedure impacts fetal circulation. Key findings from the study include:

  • Umbilical Artery Abnormalities: In 75% of cases, the UA showed transient absence of end-diastolic flow (EDF), with some progressing to reversal of EDF.
  • Timing of Changes: These abnormalities often appeared after the uterus was exteriorized but before CO2 insufflation, or after uterus replacement but before skin closure.
  • Ductus Venosus Stability: The DV generally remained stable, with only elevated pulsatility index observed in some cases, but without absent or reversed blood flow.
  • Resolution of Abnormalities: Follow-up scans one day after surgery demonstrated resolution of UA and DV Doppler abnormalities in all fetuses.
These findings suggest that transient Doppler abnormalities, particularly in the umbilical artery, can occur during fetoscopic MMC repair. Although the clinical significance of these changes remains unclear, the study highlights the importance of continuous monitoring and careful management during fetal surgery.

Looking Ahead: Improving Fetal Surgery Outcomes

While fetoscopic MMC repair offers significant advantages over traditional open surgery, further research is needed to fully understand the implications of transient Doppler abnormalities. Continuous monitoring, refined surgical techniques, and a collaborative approach among medical professionals are essential to optimizing outcomes and ensuring the well-being of both mother and child.

About this Article -

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Everything You Need To Know

1

What exactly is myelomeningocele?

Myelomeningocele (MMC) is a birth defect where the spinal cord does not close completely during pregnancy. This can lead to a range of disabilities including problems with mobility, bowel and bladder control, and other neurological issues. The severity of these issues can vary widely depending on the location and extent of the spinal defect.

2

What is fetoscopic surgery and how is it different than open fetal surgery?

Fetoscopic surgery is a minimally invasive surgical technique performed on a fetus while it is still in the womb. Small incisions are made in the mother's abdomen to access the uterus and perform the necessary repairs using specialized instruments and a camera. This approach aims to correct certain birth defects, like myelomeningocele, before birth, potentially improving outcomes compared to traditional postnatal surgery.

3

What is the Management of Myelomeningocele Study and why is it important?

The Management of Myelomeningocele Study demonstrated that prenatal repair of MMC can lead to better neurodevelopmental outcomes for the child compared to waiting until after birth for surgical intervention. This study was significant because it provided evidence supporting the benefits of intervening early to minimize the impact of the defect on the child's development.

4

What is monitored during fetoscopic MMC repair and why?

During fetoscopic MMC repair, doctors monitor the blood flow in the fetus using Doppler ultrasound. They specifically look at the umbilical artery (UA), which carries blood from the fetus to the placenta, and the ductus venosus (DV), a blood vessel that carries oxygenated blood to the fetal heart. Changes in blood flow in these vessels can indicate how the fetus is responding to the surgery.

5

What did the study discover about blood flow changes during fetoscopic MMC repair?

The study found that transient abnormalities, such as the absence or reversal of end-diastolic flow (EDF) in the umbilical artery (UA), can occur during fetoscopic MMC repair. While the ductus venosus (DV) generally remained stable, some cases showed elevated pulsatility index. Follow-up scans showed these Doppler abnormalities usually resolve on their own after the surgery. Further research is needed to understand the clinical significance of these transient changes.

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