A recent study found that mothers of twins are at double the risk of heart disease in the year after giving birth compared to mothers who give birth to a single infant. The research, led by Professor Cande Ananth and Dr. Ruby Lin from Rutgers Robert Wood Johnson Medical School in New Jersey, highlights differences in cardiovascular health between mothers of twins and those of singletons.
The study, which analyzed data on 36 million births from the Nationwide Readmissions Database between 2010 and 2020, revealed that the rate of readmissions for cardiovascular diseases within a year of childbirth was higher for women with twins—1,105.4 per 100,000 births—compared to those with single pregnancies, who had a rate of 734.1 per 100,000 births.
"The mother's heart works harder during a twin pregnancy compared to a single fetus pregnancy, and it takes longer to return to its normal state after delivery," explained Dr. Ruby Lin, the lead author of the study. "Mothers who have given birth to twins should be aware that the risk of developing heart complications is high during the first year after delivery, even if they did not have health problems during pregnancy," she added.
The risk of developing heart diseases was even greater for mothers of twins who had high blood pressure during pregnancy. Their hospitalization risk was more than eight times higher compared to mothers with singleton pregnancies who also had high blood pressure. Mothers of twins with normal blood pressure had about double the chances of being hospitalized with cardiovascular diseases compared to mothers of single pregnancies with normal blood pressure.
The study found that one year after childbirth, deaths from any cause, including heart disease, were higher among patients with single pregnancies and high blood pressure compared to patients with twins and high blood pressure. The researchers suggest that this indicates the cardiac risk is greater in the short term among twin mothers, while risk factors may persist among single-child mothers in the long term.
"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," said Professor Cande Ananth. "The rate of twin pregnancies worldwide has risen in recent decades, driven by fertility treatments and older maternal ages," he noted.
The researchers divided the participants into four groups: mothers who gave birth to twins with normal blood pressure, mothers who gave birth to twins with high blood pressure during pregnancy, mothers who gave birth to a single child with normal blood pressure, and mothers who gave birth to a single child with high blood pressure during pregnancy, as detailed by khq.com. They calculated the rate of patients readmitted to the hospital in the first year after childbirth with any type of cardiovascular disease, including heart attack, heart failure, or stroke.
Gestational hypertensive disease, which includes hypertension during pregnancy, preeclampsia, and eclampsia, was identified as a factor in the increased risk, as reported by Capital. However, the researchers clarified that they could not examine key risk factors for cardiovascular diseases, such as race and ethnicity, smoking, obesity, and drug use, as these were not consistently recorded in the database.
In a companion article, Dr. Katherine Economou from Brigham and Women's Hospital in Boston pointed out that about 33% of pregnancy-related deaths are due to cardiovascular events. "We should embrace the fourth trimester, that is, twelve weeks after childbirth, as a critical time period for making significant changes that will affect long-term cardiovascular health," she added. Dr. Economou referred to a "knowledge gap" regarding pregnancy and cardiovascular disease, particularly concerning twin pregnancies, which account for 3.1% of such cases and have increased due to fertility treatments and older maternal ages.
To address this gap in knowledge, the researchers presented new data showing differences in one-year risk of cardiovascular disease hospitalizations and mortality between singleton and twin pregnancies with and without hypertensive diseases of pregnancy, as reported by Proto Thema. "Collaboration between obstetricians, cardiologists, and other specialist physicians is essential to address maternal mortality and reduce postpartum complications," emphasized Dr. Economou.
The study also found that among women who gave birth to a single child, those with high blood pressure during pregnancy had a higher mortality rate after delivery. In contrast, among mothers of twins, the risk of mortality after delivery was lower. The researchers suggest that this finding indicates a reduction in long-term risk for mothers of twins, while mothers with singleton pregnancies may have other pre-existing cardiovascular risk factors.
Given the higher risks, the researchers emphasized that women undergoing fertility treatments, especially those who are older or have conditions such as obesity, diabetes, hypertension, or heart diseases, should be informed that twin pregnancies may increase the risk of heart-related complications in the near term.
Previous studies showed 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," noted Ananth, according to wvnews.com. The new findings underscore the importance of monitoring cardiovascular health in mothers of twins, especially in the crucial first year postpartum.
The article was written with the assistance of a news analysis system.