18 per 100,000 live births: The most recent data from the CDC in 2005 suggest approximately 18 cases of myelomeningocele per 100,000 live births in the United States. This rate is down from 28 cases per 100,000 in 1995. The decrease is likely due to increased prenatal diagnosis as well environmental factors such as prenatal vitamins (9).
Incidence higher in subsequent births: The incidence of a subsequent child with myelomeningocele is much higher if there is a previous child with a myelomeningocele (10). The risk of an affected second child is 2–3%, and the risk of an affected third child is over 10%.
Present at birth
Females > males: There is a slightly higher incidence in females (11).
Varies with location: The incidence varies among countries (12). Ireland has a particularly high incidence.
Hispanics have higher neurological level: Higher levels of the lesions are observed in Hispanics (13). It is unclear as to whether this occurrence is related to genetics, socioeconomic status, or religious beliefs concerning termination of pregnancy. The overall incidence is not higher in the Hispanic population (14).
Folate: Maternal consumption of folic acid is associated with a decreased incidence of myelomeningocele (11, 15, 50). The US rate has dropped significantly over the last decade because of the greater adherence to prenatal vitamins, folic acid fortification of breakfast cereals starting in 1998, and the greater prenatal diagnosis with option for termination.
Diet: A maternal Mediterranean diet is associated with a lower incidence of myelomeningocele (16).
Other: Other causes of myelomeningocele are anticonvulsants, especially carbamazepine, phenytoin, phenobarbital and valproic acid, acetazolamide, maternal pregestational diabetes, and obesity (11, 17).
Relationships to Other Disease States and Syndromes
Chiari II: Nearly all infants with myelomeningocele have Chiari II malformation (1, 51).
Hydrocephalus: 80% of patients with myelomeningocele develop hydrocephalus (52).
Orthopedic deformities: 64% of patients with myelomeningocele require at least one orthopedic procedure, and an average of 5.4 orthopedic procedures is required per patient (53).
Genetic anomalies: There are genetic links with Meckel syndrome, anterior sacral meningocele with anal stenosis, Mohr syndrome, trisomies 13 and 18, and 13q deletion (54-57).
Latex allergy: 20–65% of patients have latex allergy; anaphylaxis in the operating room is 500-fold greater than in patients without myelomeningoceles (58).