**3. Congenital anomalies of the central nervous system (CNS)**

Malformations of the central nervous system (CNS) are among the most common types of major congenital anomalies. Ultrasound examination is an effective modality for prenatal diagnosis of these anomalies. Poor timing of the examination, rather than poor sensitivity, can be an important factor in failing to detect a CNS abnormality [14]. Ideally, pregnancies at increased risk of fetal CNS anomalies and those with suspicious findings on a basic examination should undergo fetal neurosonography performed by clinicians with expertise in this area. Magnetic resonance imaging (MRI) is an option for further evaluation in cases of diagnostic uncertainty when additional information will influence subsequent management of the pregnancy [15].

#### **3.1. Holoprosencephaly**

at 26–41 weeks (including three deaths at 37, 39, and 41 weeks). However, there is no strong evidence of the value of this practice and antepartum fetal testing with the nonstress test, biophysical profile, or fetal movement count has not been tested specifically in this clinical setting. The type of test depends on the underlying abnormality; for example, the biophysical profile is particularly useful in fetuses with arrhythmias and provides an opportunity to monitor for development or progression of hydrops in any fetus with severely altered

• Fetal therapy. Transplacental medical therapy can improve the prognosis of some fetal arrhythmias [1]. Invasive in utero cardiac intervention (aortic or pulmonary balloon valvuloplasty, atrial needle septoplasty) may improve the prognosis of some lesions, such as HLHS or severe valvular abnormalities (severe mitral regurgitation, aortic stenosis, pulmonary atresia). Current evidence on the effectiveness of prenatal intervention for CHD derives mostly from case reports and a few larger series; although the results of the metaanalysis are encouraging in terms of perinatal survival, they should be interpreted with

• Delivery place. Delivery should be planned at a facility with the appropriate level of care for the mother and neonate. Neonates with ductal-dependent lesions and most with critical cardiac lesions should be delivered at a facility with a level III NICU and pediatric cardiology expertise. If this is not feasible, transport arrangements should be established in


fetalis

fetalis


**Table 2.** Need for specialized delivery room care in specific anomalies.



ratio < 3) or abnormal hyperoxia test in the third trimester




indicated in neonatal intensive care unit





caution when comparing with procedures performed after delivery [10].

hemodynamics.

472 Congenital Anomalies - From the Embryo to the Neonate

**2.2. Delivery management**

advance of delivery [1].

Specialized delivery room care is recommended for fetuses with:

Specialized delivery room care planning is reasonable for fetuses

Specialized delivery room care planning may be considered in

Specialized delivery room care is not needed for fetuses with:

with:

fetuses with:

Holoprosencephaly is a fetal anomaly that cannot be altered or treated. Elective termination of pregnancy is recommended if the diagnosis is made early (till 22–24 weeks of gestation under the pregnancy termination law in different countries). Because approximately 30–50% of fetuses with this anomaly have chromosomal abnormalities, prenatal karyotype is recommended. A family history (the familial recurrences have been reported), the history of current pregnancy (exposure to ethanol, salicylates) should be obtained, the evaluation for cytomegalovirus should be done. If the parents choose the conservative management, there is no fetal intervention for this condition and the cesarean delivery should be considered only for maternal indications [16].

#### **3.2. Agenesis of the corpus callosum**

During routine screening for fetal anomalies at 20–22 weeks of gestation, the two most important clues that the corpus callosum needs further assessment to exclude a callosal abnormality are (1) non-visualization of the cavum septi pellucidi and (2) ventriculomegaly (lateral ventricles measuring >10 mm). The cause of this anomaly may be genetic, infectious (TORCH infections and Zika virus), vascular, or toxic (alcohol—fetal alcohol syndrome). Callosal dysgenesis was isolated in only 24% of the fetuses, and isolated callosal abnormalities are associated with normal neurodevelopmental outcome in approximately two-thirds of fetuses [17].

most cases, the cyst, ventricular dilatation, and cisterna magna enlargement occur slowly, rarely severe or rapidly increasing ventriculomegaly needs for obstetrical intervention [16].

Management of Pregnancy and Delivery in Prenatally Diagnosed Congenital Anomalies

http://dx.doi.org/10.5772/intechopen.71802

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Anencephaly is the most common neural tube defect (NTD) [20]. The anencephalic fetus can be definitively identified by the 12th postmenstrual week by TVS; although in some cases, this diagnosis has been made as early as 9–10 postmenstrual weeks [21]. Early diagnosis can be made if the cranium is examined carefully at the time of nuchal translucency

Up to 75% of anencephalic infants are stillborn. Liveborn infants generally die within hours but occasionally survive for a few days or weeks. There are no neurosurgical management options. In most developed countries where abortion is legal, these pregnancies are interrupted earlier [23]. Because of their poor prognosis, anencephalic infants have been considered as potential organ donors for transplantation. The clinical cases reported that anencephalic infants are not good candidates for organ donation because they do not generally meet criteria for brain death until their clinical condition has declined to the point where the solid organs are damaged [24]. Polyhydramnios develops in up to 50% of the cases during the second and third trimester due to decreased fetal swallowing, but is not present during the

Prevention is the most important aspect of management of anencephaly. Periconceptional folic acid supplementation is recommended for all women who are pregnant or who may become pregnant. Higher doses of folic acid supplements are usually recommended for women who are taking anticonvulsant drugs or who have had a previous pregnancy affected by a NTD.

Because polyhydramnios is often associated with this condition, the rate of premature labor is increasing. Labor and delivery are frequently associated with an unstable fetal position, dystocia of labor, placental abruption, and postpartum hemorrhage. The cesarean delivery

Exencephaly has been detected as early as the 10th postmenstrual week. In the second trimester, the usual appearance of the cranium encasing the brain is lost. The exposed brain has

The cesarean delivery should be considered only for maternal indications.

There is no fetal intervention for DWM.

*3.3.2. Delivery management*

*3.4.1. Pregnancy management*

**3.4. Anencephaly**

measurement [22].

first trimester [20].

*3.4.2. Management of labor*

**3.5. Exencephaly**

should be considered only for maternal indications.
