What Disqualifies You From MMC Fetal Surgery?

Being told you do not qualify for fetal surgery for your baby’s myelomeningocele (MMC) can be heartbreaking, and it is natural to wonder why. The medical team evaluates strict criteria for both the baby and the mother. When a mother is disqualified, it is because the procedure poses too great a risk to her own life and health ^[1]. Fetal surgery involves opening the abdomen and the uterus to reach the baby, carrying significant maternal risks ^[2][3]. To balance the potential benefits for the baby against the dangers to the mother, doctors rely on strict eligibility rules originally established by a landmark study called the Management of Myelomeningocele Study (MOMS) ^[4].

Common Maternal Medical Exclusions

The medical exclusions for fetal surgery are not judgments about your worthiness as a mother; they are essential safety boundaries. While there are also fetal criteria (such as the baby’s gestational age or the presence of other genetic anomalies), common reasons a mother may be medically disqualified include:

• A High Body Mass Index (BMI): The original MOMS trial criteria excluded mothers with a BMI of 35 or higher ^[4][5]. Higher BMI can complicate surgery and anesthesia, increasing the risk of complications. However, some specialized centers are beginning to re-evaluate this rule, finding that a BMI up to 40 might still be safe in certain cases ^[5][6].
• Previous Uterine Surgeries: If you have had prior surgeries that involved cutting into the muscle of the uterus, such as a classical C-section (which uses a vertical incision) or a myomectomy (removal of uterine fibroids), you may not qualify ^[7]. These surgeries leave a scar that significantly increases the risk of uterine rupture (the uterus tearing open) during the current pregnancy or surgery ^[3].
• High Risk for Extreme Preterm Labor: Open fetal surgery itself increases the risk of delivering the baby prematurely ^[8]. If you already have a high risk for preterm labor—such as a short cervix or a history of very early deliveries—the surgery might trigger a dangerously early birth ^[8][9].
• Certain Infections: Mothers who test positive for chronic infections like HIV, Hepatitis B, or Hepatitis C have historically been excluded from open fetal surgery ^[7]. This is to protect both the mother and the medical team during a complex operation. Like the BMI rule, some centers are now looking at these cases individually, sometimes offering surgery to mothers with well-controlled HIV ^[10][7].

Protecting Your Life and Health

It is crucial to understand that maternal exclusion criteria exist primarily to protect your life ^[11]. Open maternal-fetal surgery requires a hysterotomy (a surgical incision into the uterus) ^[3]. This creates a significant risk of uterine rupture and dehiscence (the surgical wound opening up) not only during your current pregnancy but also in any future pregnancies ^[3][2]. Note that some centers offer minimally invasive fetoscopic surgery, which avoids the large uterine incision and may have different risks, though strict criteria still apply ^[12].

The decision to exclude a mother is made by a large, specialized medical team dedicated to keeping you safe ^[13]. If you are told you do not qualify, it means the team believes the threat to your life or the extreme risk of a premature delivery outweighs the potential benefits of closing your baby’s spine before birth ^[1]. While disappointing, it ensures that you remain healthy and able to care for your baby. Remember that postnatal surgery—closing the baby’s spine safely within the first few days after birth—remains a standard, highly developed, and widely successful procedure.