Scientists have linked maternal hypertension before pregnancy with heart defects in children

A woman's health before pregnancy may be related to the development of the unborn child's cardiovascular system. Scientists have found that chronic hypertension and type I or type II diabetes in the mother are associated with an increased likelihood of severe congenital heart defects in newborns. The researchers came to these conclusions after analyzing data from more than 44 million births in the United States. About which diseases of the mother the scientists studied and how noticeable the connection turned out to be, see the Izvestia article.

Hypertension and diabetes have been linked to heart defects

The researchers analyzed data on more than 44 million births in the United States between 2018 and 2024. Almost 28,000 infants, or 0.06% of the total, were diagnosed with critical congenital heart defects, the most severe group of such disorders.

According to the results, maternal chronic hypertension was associated with a 30% increased chance of having a child with a critical heart defect compared with pregnancies in which the woman did not have high blood pressure. If the mother had type 1 or type 2 diabetes before pregnancy, the child was 48% more likely to have such disorders.

Separately, the scientists examined gestational hypertension, an increase in blood pressure that occurred after the 20th week of pregnancy. In this group, the probability of critical congenital heart defects in children was 8% higher. However, eclampsia did not show a statistically significant association with such disorders.

The results of the study are presented to the American Heart Association (AHA). The preliminary results are published in the journal Medical Xpress. The work has not yet been published as a full-fledged article in a peer-reviewed scientific journal.

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What violations have scientists studied?

The study is devoted to critical congenital heart defects. This is the most severe group of congenital cardiac disorders. Children with such diagnoses require surgery or catheter insertion during the first year of life, as well as further follow-up by cardiologists.

Scientists noted that the prevalence of critical heart defects in the United States increased by about 10%: from 5.8 cases per 10,000 births in 2018 to 6.4 cases per 10,000 in 2023-2024. During the same period, the prevalence of hypertension in pregnant women increased by almost 48%, from about 9.4% to 13.9%.

The authors of the work drew attention to the fact that the indicators changed simultaneously. However, this does not mean that the increase in the number of hypertension cases by itself explains the increase in the prevalence of heart defects: the study assessed the relationship between maternal conditions and diagnoses in children, rather than establishing a single cause of the changes.

Why it is important to consider the health of the mother before conception

The study distinguished between chronic and gestational hypertension. The first category included high blood pressure that existed before pregnancy or was diagnosed before the 20th week. Gestational hypertension, on the contrary, occurred after the 20th week of pregnancy. The authors found a more pronounced association with critical heart defects in chronic hypertension than in gestational hypertension.

Rahman also stressed the need to monitor blood pressure and discuss the state of the cardiovascular system with doctors before and during pregnancy. According to him, this is important to reduce the likelihood of congenital heart defects in a child.

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Why are the results still considered preliminary?

The authors used data from the US national Birth certificate database. This approach allowed us to analyze a very large sample, but the study has limitations. In particular, the database does not contain complete information about genetic factors, maternal health history, results of prenatal diagnosis, timing and severity of hypertension, as well as treatment and effectiveness of blood pressure control.

The researchers emphasize that in the future it is necessary to study the biological mechanisms that may explain the link between increased maternal blood pressure and critical congenital heart defects. It is also necessary to find out whether the probability of violations depends on the time of onset of hypertension, its severity and treatment.

According to the expert, the data obtained complement the growing number of scientific evidence on the relationship between maternal health and the intrauterine environment with the development of the fetal cardiovascular system.