Congenital heart disease risks in pregnancy “may be overestimated’

Women with congenital heart disease are more likely to have safer pregnancies, according to new research.

Physicians may have been over-estimating the risks of complications for women with these disorders, which in turn may have been discouraging them from pregnancy, the researchers said.

Congenital heart disease (CHD) is a group of abnormalities in the heart that develop before birth, such as holes in the heart, leaky or narrow valves, and incomplete or missing parts. The condition is relatively rare, but affects nearly one percent of all babies born in the United States each year.

The new research from the Perelman School of Medicine at the University of Pennsylvania reveals that women with CHD, deemed high risk by conventional measures, are in fact more likely to have safe, healthy pregnancies than current risk-assessments suggest.

"Our findings are extremely promising for women with CHD who are entering their childrearing years, as we now know there is a better chance of a healthy, low-risk pregnancy," said the study's lead author, Dr Yuli Kim, who is director of the Philadelphia Adult Congenital Heart Centre, and an assistant professor of Medicine in the Perelman School of Medicine at the University of Pennsylvania.

“With the tools currently used to evaluate risk, such as Pregnancy and Congenital Heart Disease (ZAHARA) and Cardiac Disease in Pregnancy (CARPREG) risk scores, clinicians have actually been over estimating the risk of complication for some of these women, which could be discouraging when making the decision to have children,” she explained.

As part of the study, the researchers examined 186 women over 18 with CHD who had given birth between 1998 and 2014, and applied risk scores from CARPREG and ZAHARA. Cardiac events, such as arrhythmia, heart failure, stroke, heart attack, cardiac arrest, or cardiac death, were assessed for up to six months after birth.

While there were 31 cardiac events – representing 17 percent of all pregnancies – none of the women died. With the CARPREG model, the estimated risk versus observed adverse events differed greatly from 75 to 25 percent, and with ZAHARA, estimated risk was 70 percent and observed events were 38 percent.

“Risk assessment tools are very beneficial on a global scale, but the best way to evaluate patients and determine potential risk is to evaluate each patient on an individual level,” Dr Kim said.

“The results from this study will certainly be helpful in reassuring woman with CHD that most patients in similar situations have successful pregnancy, especially if they are managed in a high-risk clinic.”

She noted that additional research is needed in order to better identify higher risk patients, but that this data will be helpful in the clinical management of CHD patients who are navigating their pregnancy.

The findings of the research will be presented at the American Heart Association Scientific Sessions 2016 in December.

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