Fetal surgery is a highly specialized medical procedure performed on a developing fetus while it is still inside the mother’s uterus (in utero surgery). This intervention is reserved for life-threatening or severely disabling birth defects that, if left untreated, would result in irreversible damage or death. A multidisciplinary team, including maternal-fetal medicine experts, pediatric surgeons, and anesthesiologists, collaborates on these operations. The goal is to correct the anatomical defect or halt the progression of the condition during the window of fetal development.
Conditions Requiring Intervention
The decision to proceed with surgery is based on the condition’s severity and the potential for long-term improvement. One of the most common conditions addressed is Myelomeningocele, the most severe form of Spina Bifida, where the spinal cord is exposed. Prenatal repair can significantly reduce the need for a shunt to treat hydrocephalus and may improve motor function.
Twin-to-Twin Transfusion Syndrome (TTTS) often requires in utero intervention, typically laser ablation. This syndrome occurs in monochorionic twin pregnancies when abnormal blood vessel connections in the shared placenta cause unequal blood flow between the twins. Fetal surgery also addresses structural issues like Congenital Diaphragmatic Hernia (CDH), where a hole in the diaphragm allows abdominal organs to move into the chest cavity, preventing lung development.
Other interventions target blockages or mass lesions that compromise fetal circulation or airway development. Congenital High Airway Obstruction Syndrome (CHAOS) or large neck masses can be managed to secure the baby’s airway before delivery. Certain congenital heart defects and lower urinary tract obstructions may also be treated with less invasive procedures to prevent damage to the heart or kidneys.
Approaches to Operating on the Fetus
Fetal surgeons utilize two primary methods to access the fetus, which differ significantly in invasiveness. The traditional approach is Open Fetal Surgery, a major abdominal operation similar to a Cesarean section. This technique involves a large incision across the mother’s abdomen to expose the uterus.
The surgeon then makes an incision into the uterus, which is held open with specialized devices to prevent bleeding and maintain the amniotic environment. The fetus is partially delivered, allowing the surgical team to perform the repair before placing the baby back inside. Open surgery is typically performed for complex structural defects like Myelomeningocele repair or the resection of large tumors such as a Sacrococcygeal Teratoma.
Minimally Invasive or Fetoscopic Surgery is a less traumatic alternative that uses small instruments and a camera. The surgeon inserts a thin, fiber-optic telescope (a fetoscope) through tiny ports, or trocars, placed through the mother’s abdomen and into the uterus. This method avoids the large hysterotomy incision, leading to an easier post-operative recovery for the mother.
Fetoscopic techniques are preferred for procedures such as laser ablation for TTTS or shunt placements for fluid buildup in the chest or urinary tract. The choice between open and fetoscopic surgery depends on the specific fetal condition and the gestational age.
The Surgical Journey: Steps of the Procedure
The surgical journey begins with pre-operative planning, including detailed imaging and anesthesia consultation for both the mother and the fetus. For open procedures, the mother is placed under general anesthesia, which provides pain relief and ensures the uterus is relaxed. The anesthetic agents cross the placenta, providing anesthesia and immobility for the fetus.
Uterine management is a central component of the surgery, primarily through medications called tocolytics. These agents, such as magnesium sulfate or volatile anesthetic gases, are administered to suppress uterine contractions triggered by surgical manipulation. Preventing contractions is paramount to maintaining blood flow to the placenta and avoiding premature labor.
During the operation, specialized equipment is used for continuous Fetal Monitoring, including Doppler ultrasonography and echocardiography. These tools allow the surgical team to track the baby’s heart rate, rhythm, and blood flow, signaling any distress. In some cases, the fetus may receive an injection of muscle relaxants or pain medication directly to ensure stillness during the repair.
After the surgical repair is complete, Uterine Closure begins. In open surgery, the uterine incision is meticulously repaired in multiple layers, often using a stapling device or sutures to ensure a strong, watertight seal. The amniotic fluid lost during the procedure is then replaced with warmed crystalloid solution to restore the baby’s environment before the mother’s abdominal wall is closed.
Post-Operative Care and Delivery Planning
Immediately following the procedure, the mother is admitted for several days of intensive monitoring, typically in a specialized maternal-fetal care unit. This period focuses on managing pain and preventing preterm labor, the most significant risk after surgery. The mother remains on continuous tocolytic therapy to maintain uterine quiescence.
Once discharged, the mother is often placed on restricted activity for the remainder of the pregnancy. Weekly follow-up appointments, including frequent ultrasounds, monitor the integrity of the uterine repair and the baby’s growth. The goal is to prolong the pregnancy as close to term as safely possible to allow for maximal fetal development.
The delivery plan is impacted by the surgical approach used. Following Open Fetal Surgery, a planned Cesarean section is almost always required for the current and all future pregnancies. The scar on the uterus carries a risk of uterine rupture during labor contractions, which could be catastrophic for both mother and baby.
In contrast, mothers who undergo Minimally Invasive Fetoscopic Surgery may retain the option for a vaginal delivery, provided their individual circumstances permit it. Regardless of the route, delivery is typically planned in a specialized hospital setting with immediate access to a neonatal intensive care unit and pediatric specialists.