*3.2.3 Spina bifida Occulta*

Abnormal development of the embryonic tail bud results in a wide range of spinal cord abnormalities grouped as spina bifida occulta (**Figure 2**). It is generally accompanied by other skeletal defects such as sacral agenesis. The anomaly mostly involves sacral and lower lumbar vertebrae.

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of anencephaly [26].

*Common Congenital Neural Tube Anomalies: Epidemiology, Classification, Management…*

Despite recent progress in epidemiologic and clinical research, the exact etiology of NTDs has remained undetermined. It is in common agreement that the interactions between genetic and environmental factors are the possible etiopathogenic factors [14, 15]. More than 70% of cases of NTDs are found to have a genetic etiology [16]. Some of the potential non-genetic environmental risk factors for NTD-affected

pregnancy are poor socioeconomic status, maternal hyperthermia; maternal exposure to high doses of irradiation, certain chemicals, and drugs; cigarette smoking; maternal metabolic diseases, and advanced parental age, including those of both mother and father. Pregnancies associated with a fetus with NTD have higher chances of going into preterm labor and being delivered prematurely [5, 17, 18]. In 2008, a large study in California reported that mothers who do not graduate from high school or live in neighborhoods under poor socioeconomic conditions have a greater risk of delivering an NTD-affected child [19]. Brough et al. elaborated in their study that the mothers with higher socioeconomic and educational levels are more likely to consume folic acid during preconception and early gestational age when the neural tube is developing [20], and this might have contributed to the findings of the California study. A meta-analysis regarding the effect of maternal age on the risk of NTD reported that mothers older than 40 and younger than 19 years of age had increased risks of NTD-affected pregnancies [21], the chances being higher for spinal Bifida but not for anencephaly. Studies have assessed the role of parental occupational exposures in the development of NTDs. Brender et al. found self-reported multiple pesticide exposure to be a risk factor for fetal NTD [22]. The role of paternal exposures to hazardous materials in increasing the risk of NTDs in offsprings was emphasized when studies showed that fathers who work as a cook, gardener, janitor, and cleaner have higher chances of getting a child with spina bifida, as these professions have a higher likelihood of exposure to hazardous chemicals [23]. The occupational exposure of fathers to metal-working oil mists and hydrocarbons do not show any association with NTD risk [24]. Caffeine has been investigated as another risk factor for NTDs. Past studies have shown that higher Caffeine consumption during the year before pregnancy increases the risk of spina bifida [25]. The use of antimicrobial medications during the preconception period and first trimester of pregnancy are found to be associated with a higher risk

*DOI: http://dx.doi.org/10.5772/intechopen.97182*

**4. Etiology and embryology**

**Figure 5.**

*Diagrams of encephalocele.*

*Common Congenital Neural Tube Anomalies: Epidemiology, Classification, Management… DOI: http://dx.doi.org/10.5772/intechopen.97182*

**Figure 5.** *Diagrams of encephalocele.*

*Congenital Anomalies in Newborn Infants - Clinical and Etiopathological Perspectives*

Meningocele is the protrusion of meninges through the vertebral arch defect without the spinal cord (**Figure 4**) [13]. This defect is macroscopically similar to

Abnormal development of the embryonic tail bud results in a wide range of spinal cord abnormalities grouped as spina bifida occulta (**Figure 2**). It is generally accompanied by other skeletal defects such as sacral agenesis. The anomaly mostly

myelomeningocele with differences in the contents of the herniated sac.

*Diagram showing spina bifida occulta, memingocele and myelomeningocele.*

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*3.2.2 Meningocele*

**Figure 4.**

**Figure 3.**

*Diagram showing anencephaly.*

*3.2.3 Spina bifida Occulta*

involves sacral and lower lumbar vertebrae.
