Maternal chronic disease linked to higher rates of congenital heart disease in babies

Pregnant women with congenital heart defects or type 2 diabetes have a higher risk of giving birth to babies with severe congenital heart disease and should be monitored closely in the prenatal period, according to a study published in CMAJ (Canadian Medical Association Journal).

The study, of almost 4 million births in Taiwan, also found a slightly higher risk of mild congenital heart disease in offspring of mothers with diabetes (type 1 or 2), high blood pressure, congenital heart disease, anemia, epilepsy and several other chronic diseases. However, the authors caution that the risk is small.

"Although some maternal diseases were associated with congenital heart disease in offspring, caution should be applied in interpreting these associations, because the population attributable risks were very low," writes Dr. Chung-Yi Li, Institute of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan, with coauthors.

Congenital heart disease is the most common pre-existing health condition in newborns, ranging from 5 to 15 of every 1000 live births. It is the number one cause of death in newborns.

The researchers found a higher rate of congenital heart disease in the Taiwanese sample population -- almost 20/1000 live births -- compared with other countries, and suggest that the increased use of fetal echocardiography may be detecting more cases. They also found an unexpected decrease in the number of cases of severe congenital heart disease, and postulate that the more frequent use of antenatal diagnostic techniques may be leading more parents to terminate pregnancies with known cardiac abnormalities.

"The results of the current study are of value for preconception counselling and the identification of high-risk pregnant women," write the authors. "For pregnant woman who are at high risk, more frequent prenatal screening (with fetal echocardiography) may be warranted. Early recognition of congenital heart disease also permits optimal preparation and care during pregnancy, delivery and the postnatal period."

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