Genetic testing can provide better support for pregnant women with hereditary heart disease risk.
Women who carry a specific gene variant in the Titin gene appear to have a higher risk of developing heart failure in connection with pregnancy than most women. At the same time, the vast majority coped well with pregnancy, and pregnancy did not result in any lasting negative changes to the heart, according to a new study from ProCardio at Oslo University Hospital Rikshospitalet.
Photo: Siri Holm Solberg
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Pregnancy-related heart failure, known as peripartum cardiomyopathy, is rare and occurs in between 0.02 and 0.1% of live births in European countries.
Genetic variants that shorten the protein Titin, referred to as TTNtv, are the most common genetic finding in women diagnosed with this condition. However, there has been little knowledge about how women with such genetic variants cope with pregnancy.
107 women followed over time
ProCardio, Section for Cardiogenetics at Oslo University Hospital, Rikshospitalet, has followed 107 women who carry the TTNTV genetic variant. Some of them showed signs of heart disease, while others were healthy, but all had undergone at least one heart examination. The researchers at ProCardio mapped previous pregnancies and the outcomes for both mother and child using questionnaires and medical records.
78 of the women had been pregnant a total of 206 times, and 167 of these pregnancies resulted in the child being born alive (81%). Almost all had given birth before they were aware that they carried the genetic variant, and 17% of the women were probands, meaning they were the first in their family to be diagnosed.
Three developed heart failure
Three of the women developed heart failure towards the end of their pregnancy or shortly after giving birth. This corresponds to 1.8% of the births and 3.9% of the women who had given birth. This rate is significantly higher than that observed in births generally.
All three were young, expecting one child, did not have pregnancy-induced hypertension, and were unaware that they carried the genetic variant. Thus, they lacked the usual risk factors for heart failure during pregnancy. All three received treatment, and one year later, their heart function was normal or only mildly reduced. None of them died or required a heart transplant.
The researchers believe that the heart failure in these women was likely an early manifestation of hereditary heart disease, triggered by the strain that pregnancy imposes. Without genetic testing, these cases would likely have been recorded as typical pregnancy-related heart failure.
Most pregnancies went well
About one-third of the women experienced symptoms such as palpitations or shortness of breath during pregnancy, which is also common among pregnant women in general. Aside from the three who developed heart failure, none required hospitalisation or examination by a cardiologist. None of the women experienced heart failure in subsequent pregnancies, and the risk did not increase with the number of children.
The children also fared well. Complications such as premature birth and low birth weight were not more common than in the general population.
No lasting effects on the heart
The pregnancy also does not appear to harm the heart in the long term. After a median of 18 years following the first birth, the researchers found no differences between women who had given birth and those who had not, in terms of arrhythmias, heart function, or the size of the heart chambers. Pregnancies were well tolerated and were not associated with adverse long-term changes (remodelling) of the heart.
Important to provide guidance before pregnancy
The researchers believe the findings indicate that women with the genetic variant should receive guidance before becoming pregnant and be monitored by a cardiologist throughout their pregnancy. At the same time, the results are reassuring for women with the Titin genetic variant who wish to have children.
The study is small, and much of the information about previous pregnancies is based on the women's own recollections. None of the women had known heart disease before pregnancy, so the findings do not necessarily apply to women who already have dilated cardiomyopathy.