Cardiac Risk Score to Predict Small for Gestational Age Infants in Pregnant Women With Heart Disease

One of the most common fetal complications in pregnant women with cardiovascular disease is a small for gestational age (SGA) neonate, which is associated with a higher risk of perinatal morbidity/mortality and poor long-term health outcomes. The objective of this study was to identify cardiac determinants and derive a risk score for clinically relevant SGA < 5th percentile (SGA-5th).

A prospective cohort of 1812 pregnancies in women with heart disease were studied. SGA-5th was the outcome of interest, defined as birth weight < 5th percentile for gestational age and sex. Multivariable logistic regression analysis was used to identify predictors for SGA-5th. Based on the regression coefficients, a weighted risk score was created.

SGA-5th complicated 10% of pregnancies, 11 predictors of SGA-5th were identified, and each was assigned a weighted score: maternal cyanosis (8), Fontan palliation (7), smoking (3), moderate or severe valvular regurgitation (3), β-blocker use throughout pregnancy (4) or only in the 2nd and 3rd trimesters (2), high baseline β-blocker dose (4), body mass index < 18.5 kg/m² (3) or 18.5-24.9 kg/m² (1), Asian/other ethnicity (2), and significant outflow tract obstruction (1). In the absence of these identified risk factors, the risk of SGA-5th was approximately 4%. Pregnancies with risk scores of 1 had a rate of 5%; 2, 7%; 3, 9%; 4, 12%; 5, 14%; 6, 18%; 7, 23%; 8, 28%; and ≥ 9, 34%.

There are a number of cardiac predictors that are associated with increased risk of SGA-5th. This is a prognostically important outcome, and consideration should be given to routinely predicting and modifying the risk whenever possible.