Mothers of twins face a higher risk of heart disease in the year after birth

Mothers of twins face a higher risk of heart disease in the year after birth

Study finds that mothers of twins with normal blood pressure during pregnancy are twice as likely to be hospitalized with cardiovascular disease within a year after giving birth than women who have a single pregnancy.

The risk of being admitted to the hospital with heart disease is twice as high the year after birth for mothers of twins compared to single births, according to research published in the European Heart Journal [1] today (Monday). The risk is even higher in mothers of twins who had high blood pressure conditions during pregnancy.

The research was led by Professor Cande Ananth, PhD, MPH, a professor in the Department of Obstetrics, Gynecology, and Reproductive Sciences at Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ.

He said: “The rate of twin pregnancies worldwide has risen in recent decades, driven by fertility treatments and older maternal ages. Previous studies have shown no long-term increased risk of cardiovascular disease when following people with twin pregnancies for decades after delivery. However, this is counterintuitive to what we observe clinically when caring for patients with twin pregnancies.

“Given the unacceptably high rate of maternal mortality in the first year after birth due to cardiovascular disease, we wanted to examine whether twin pregnancies increase this risk.”

The researchers studied data on 36 million hospital deliveries taken from the US Nationwide Readmissions Database of US hospitals from 2010 to 2020. They divided pregnant patients into four groups: those who had twins but normal blood pressure during pregnancy, those who had twins and hypertensive disease of pregnancy (high blood pressure conditions), those who had single pregnancies with normal blood pressure, and those who had single pregnancies with hypertensive disease of pregnancy.

Hypertensive disease of pregnancy includes gestational hypertension, pre-eclampsia, eclampsia, and superimposed pre-eclampsia.

For each group, researchers calculated the proportion of patients who were readmitted to the hospital within a year of childbirth with any type of cardiovascular disease, including heart attack, heart failure, or stroke.

Researchers found that the proportion of readmissions for cardiovascular disease within a year of giving birth was higher overall for those with twins (1,105.4 per 100,000 deliveries) than single pregnancies (734.1 per 100,000 deliveries).

Compared to single pregnancies with normal blood pressure, people with twins with normal blood pressure were around twice as likely to be hospitalized with cardiovascular disease. For those with twins with high blood pressure during pregnancy, the risk is more than eight times higher.

However, one year after birth, deaths from any cause, including heart disease, were higher among patients with singlepregnancies who had high blood pressure conditions compared to patients with twins with high blood pressure conditions. This suggests that the risk to mothers of twins decreases in the longer term, while the mothers of singles may have other pre-existing cardiovascular risk factors.

The researchers were not able to examine essential risk factors for cardiovascular disease, such as race/ethnicity, smoking, obesity, and drug use, because these were not consistently recorded in the database.

Dr Ruby Lin, a maternal-fetal medicine fellow at Rutgers Robert Wood Johnson Medical School and the study’s lead author, said: “The maternal heart works harder for twin pregnancies than for single pregnancies, and it takes weeks for the maternal heart to return to its pre-pregnancy state.

“People with twin pregnancies should be aware of the short-term increase in cardiovascular disease complications in the first year after birth, even if they had a pregnancy that was not complicated by high blood pressure conditions, such as pre-eclampsia.

“For patients having fertility treatments, especially for those with other cardiovascular risk factors, such as older age, obesity, diabetes, high blood pressure or heart disease, patients should be advised that twin pregnancies may increase cardiovascular disease complications in the short term.

“Given these higher risks, healthcare providers and health insurance companies should continue to provide follow-up for up to a year after birth for high-risk pregnancies such as twin pregnancies.”

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Notes:

Please acknowledge the European Heart Journal as a source in any articles:

[1] “Hospitalization for cardiovascular disease in the year after delivery of twin pregnancies”, by Ruby Lin et al, European Heart Journal. doi: https://doi.org/10.1093/eurheartj/ehaf003

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Funding: no external funding

The European Heart Journal is the flagship journal of the European Society of Cardiology. It is published on behalf of the ESC by Oxford Journals, a division of Oxford University Press.