Study finds increased risk of cardiovascular disease for mothers of twins

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 singleton births, according to research published in the European Heart Journal today (Monday). The risk is even higher in mothers of twins who had a high blood pressure condition during pregnancy.

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 singleton pregnancies with normal blood pressure, and those who had singleton 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 singleton pregnancies (734.1 per 100,000 deliveries).

Compared to singleton pregnancies with normal blood pressure, people with twins with normal blood pressure were around twice as likely to be hospitalised 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 singleton pregnancies 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 singletons may have other pre-existing cardiovascular risk factors.