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Saxena et al. Vessel Plus 2022;6:15 https://dx.doi.org/10.20517/2574-1209.2021.96 Page 5 of 17

Risk-stratification scores have been developed based on various studies to predict adverse outcomes in
women with CHD. The commonly used scoring systems include the Cardiac Disease in Pregnancy
(CARPREG) score, the modified World Health Organization (WHO) classification scores, and the
ZAHARA score [1,29,30] . The modified WHO classification system is currently recommended by both
American and European guidelines for care of women with CHD in pregnancy, although it is probably
more appropriate for developed rather than developing countries.

The modified WHO classification is primarily based on underlying congenital cardiac condition, and it also
includes lists of CHD that contraindicate pregnancy. The general principle of classification is given in
Table 1. Women in mWHO Class IV should be advised against pregnancy. Patients with a high-risk CHD
which is a contraindication for pregnancy must be counseled at a young age explaining the harmful effects
of pregnancy on their hemodynamics. It is equally important to assure women with milder forms of CHD
that they can go through pregnancy with a low risk. High-risk patients must be managed at centers with
expertise. In general, risk of pregnancy increases with increased complexity of CHD. All women with CHD
must be assessed at least once before pregnancy and then during pregnancy.

Fetal risk
The fetal risks mainly include the risk of prematurity, low birth weight/small for gestational age,
fetal/neonatal death, and the risk of recurrence of CHD. Maternal and neonatal events are highly correlated.
The risk of adverse fetal/neonatal outcome is closely correlated with the severity of impairment of maternal
hemodynamics due to the direct effect on uteroplacental blood flow. Fetal/neonatal mortality is more
frequent in women with CHD (4%) than in the general population . The risk of adverse outcomes for fetus
[31]
in maternal CHD is quite high in women with severe forms, such as univentricular physiology,
Eisenmenger physiology, and unrepaired cyanotic defects. In women with cyanotic CHD, cyanosis poses a
significant risk to the fetus, and a live birth is highly unlikely (< 12%) if oxygen saturation is below 85%,
while more than 90% of fetuses survive to birth if maternal arterial saturation is more than 90%. Some
important risk predictors of neonatal events include mothers with left heart obstruction, mechanical heart
valve prosthesis, use of oral anticoagulants, and, most importantly, maternal New York Heart Association
(NYHA) Class III/IV at baseline.

Risk of transmission of CHD in presence of a positive family history (up to third degree relatives) is variable
depending on maternal CHD type, presence of a syndrome, and other factors but is in the range of 3%-7%
and slightly higher when the affected member is the mother [Table 2] [32,33] . The recurrence risk is also higher
with heterotaxy, conotruncal anomalies, atrioventricular septal defect, and obstructive lesions of the left
ventricular outflow tract. Therefore, the chance of recurrence of CHD in offspring should be discussed with
all women with CHD. It is important to record a detailed family history and examine for syndromic features
as these can help in identifying subtle syndromes and inheritance patterns.

The etiology of CHD is multifactorial, with only 20%-30% of CHD cases having an identifiable genetic or
environmental cause . In addition, most genetic mutations in patients with CHD are sporadic.
[34]
Nevertheless, genetic testing using cord blood samples can be offered to all women with CHD with
discussion of the advantages and limitations of genetic testing. An important advantage of genetic testing is
that it can help in recognition or prediction of extracardiac comorbid conditions which can affect long-term
outcome and thus allow more accurate prognostication in some cases . Newer genetic tests such as
[34]
chromosomal microarray and next generation sequencing are now in widespread use and have increased
the chances of identifying genetic etiology of CHD but have the limitation of identifying variants of
unknown significance.