**2. Cardiovascular anomalies**

Identification and management of fetal cardiac abnormalities are important because congenital anomalies are the leading cause of infant death and congenital heart disease accounts for 30–50% of these deaths [1]. The best time for evaluating the fetal heart anatomy is 18–22 weeks of gestation, because the fetal cardiac anatomy can be visualized well at this stage of pregnancy, a complete fetal anatomic survey can be performed, and there is time for further evaluation (e.g., echocardiogram, chromosomal microarray), if indicated, while the fetus is still periviable [2]. After 30 weeks of gestation, it can be difficult to obtain good images as the fetus becomes more crowded within the amniotic cavity. Fetal arrhythmias, myocarditis, cardiomyopathy, heart failure, valvular insufficiency or obstruction and cardiac tumors have variable onset. Fetal echocardiography should be performed in fetuses at a higher risk of congenital heart disease (**Table 1**).

**2.1. Pregnancy management**

heart disease [8].

preferred site for delivery [1].

indicated.

When a fetal cardiac abnormality is detected, additional evaluation and follow-up are

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• Assessment for extracardiac anomalies. The extracardiac abnormalities are detected in 20–40% of all fetal cardiac anomalies [1, 3]; the cardiac anomalies are part of numerous fetal syndromes [4]. A systematic review and meta-analysis of studies of prenatal ultrasound and magnetic resonance imaging (MRI) found that brain abnormalities, delay in head growth, and brain-sparing were observed in subgroups of fetuses with congenital heart disease [5] However, the prognostic significance of these findings was unclear.

• Genetic assessment. Fetal genetic assessment is indicated because chromosome abnormalities are common in fetuses with cardiac defects, even when isolated [6]. Forty-one percent of fetuses with prenatally diagnosed structural cardiac defects had an abnormal karyotype [7]. The incidence in infants of congenital heart disease about 15% [6], it is higher because of in utero mortality in many cases, such as the lethal autosomal trisomies (e.g., trisomy 9 or 16). The risk of fetal aneuploidy varies depending on the malformation. For example (risk percent, [2]): atrioventricular septal defect (46–73%), truncus arteriosus (19–78%), doubleoutlet right ventricle/conotruncal malformations (6–43%), coarctation/arch interruption (5–37%), tricuspid valve dysplasia (including Ebstein malformation, 4–16%), tetralogy of Fallot (7–39 percent), hypoplastic left heart syndrome (HLHS, 4–9%), pulmonic stenosis/

• Ultrasound follow-up. The necessity, timing, and frequency of serial assessment should be guided by the nature and severity of the lesion, presence of heart failure, anticipated timing and mechanism of progression, and the options available for prenatal and postpartum intervention [2]. At least one follow-up examination early in the third trimester is reasonable in order to look for abnormalities that progressed in severity or may not have been detectable earlier in gestation and have peripartum clinical implications. Some causes of progressive fetal cardiac dysfunction include worsening valvular insufficiency or obstruction, increasing obstruction to blood flow in the great arteries, and development or worsening of myocarditis or cardiomyopathy, arrhythmias, or cardiac tumors [2]. Intrauterine fetal growth restriction is more prevalent in these fetuses with congenital

• Referral to a pediatric cardiologist. The purpose is to educate the patient about the suspected diagnosis and discuss management options before and after delivery, including the

• Evaluation of fetal well-being. Fetuses with cardiac structural anomalies, functional disorders, or arrhythmias that have the potential to compromise tissue oxygen delivery are generally followed with antepartum testing, with intervention if results are abnormal. In one retrospective cohort study, fetuses with a genetic syndrome, extracardiac anomaly, or severe valvular regurgitation were at increased risk for fetal demise: 15/197 (7.6%) fetuses with one or more of these risk factors died in utero versus 3/270 (1%) fetuses without any of these risk factors [9]. Six of the 22 fetal deaths occurred at 20–23 weeks and 16 occurred

atresia with intact septum (1–12%), and transposition of great arteries (0%).


**Table 1.** Indications for fetal echocardiography [2].

#### **2.1. Pregnancy management**

**2. Cardiovascular anomalies**

470 Congenital Anomalies - From the Embryo to the Neonate

congenital heart disease (**Table 1**).



suspected on obstetrical ultrasound

rearrangement, or aneuploidy

heart rhythm

trimester ultrasound - Monochorionic twinning - Fetal hydrops or effusions

diagnosed in the first trimester

SSA/SSB-related heart disease

paternal or sibling)







**Table 1.** Indications for fetal echocardiography [2].


inflammatory drugs [NSAIDs] in the third trimester)


Identification and management of fetal cardiac abnormalities are important because congenital anomalies are the leading cause of infant death and congenital heart disease accounts for 30–50% of these deaths [1]. The best time for evaluating the fetal heart anatomy is 18–22 weeks of gestation, because the fetal cardiac anatomy can be visualized well at this stage of pregnancy, a complete fetal anatomic survey can be performed, and there is time for further evaluation (e.g., echocardiogram, chromosomal microarray), if indicated, while the fetus is still periviable [2]. After 30 weeks of gestation, it can be difficult to obtain good images as the fetus becomes more crowded within the amniotic cavity. Fetal arrhythmias, myocarditis, cardiomyopathy, heart failure, valvular insufficiency or obstruction and cardiac tumors have variable onset. Fetal echocardiography should be performed in fetuses at a higher risk of

**Indications with higher risk profile (estimated >2% absolute risk) Indications with lower risk profile** 

**(estimated >1 and <2% absolute risk)**

first/second trimester)

relative of fetus.




When a fetal cardiac abnormality is detected, additional evaluation and follow-up are indicated.


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 hemodynamics.

• Timing and route. Cesarean delivery is performed for standard obstetrical indications, as there is no evidence that route of delivery of fetuses with congenital heart disease affects outcome [11]. Based on observational data, induction of labor or scheduled cesarean before 39 weeks of gestation is not recommended in the absence of standard maternal or fetal concerns about well-being, as even early term delivery has been associated with worse outcomes after neonatal cardiac surgery [2, 12]. One exception may be single ventricle defects,

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• Delivery room care. Risk assessment for anticipated compromise in the delivery room or

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

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 mater-

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

where earlier delivery may be beneficial [13].

pregnancy [15].

**3.1. Holoprosencephaly**

nal indications [16].

**3.2. Agenesis of the corpus callosum**

during the first few days of life is disease-specific (**Table 2**, [2]).

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

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

#### **2.2. Delivery management**

• 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 advance of delivery [1].


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

