Dr. David P. Kao, assistant professor at the University of Colorado in Denver, led the study of nearly 7.5 million women. Kao presented his results at the annual meeting of the European Society of Cardiology (ESC).
The condition, peripartum cardiomyopathy (PPCM), develops during childbirth. Experts believe women with common pregnancy-related symptoms such as shortness of breath and leg swelling plus the five PPCM risk factors could benefit from screening.
“PPCM is a type of heart failure where the heart becomes enlarged and weakened. It is a dilated cardiomyopathy that arises within one month prior to or five months following childbirth,” says Dr. Kao.
Kao says that up to 70 percent of women recover fully with normal or near-normal heart function but as many as 10-15 percent have persistent heart failure, sometimes requiring left ventricular assist device or heart transplantation. Moreover, PPCM at the time of giving birth is associated with a four to five times higher rate of stillbirth.
Kao previously published a study in four million delivering mothers which identified age 30 years or older, African ancestry, hypertension, anemia, substance abuse, asthma, autoimmune disease, multiple gestations (e.g. twins), and preeclampsia/eclampsia as risk factors for PPCM at the time of delivery.
The current study included an additional 3.5 million women with the aim of validating the risk factors and detecting others.
According to Kao, the need to identify individuals at higher risk may allow better monitoring during pregnancy.
“If there were signs that the mother’s heart was weakening, we could potentially initiate treatment with beta blockers and ACE inhibitors sooner to slow or prevent the development of PPCM, which would likely result in better outcomes.”
The study used patient records from all hospitals in California, New Jersey, Vermont, and Colorado for years varying from 2007-2013. The researchers identified nearly 3.5 million delivering mothers of whom 486 had PPCM at the time of childbirth.
They also included the four million delivering mothers (535 with PPCM) from the previous study for a total of 7.5 million women.
The researchers discovered for the first time that obesity and mood disorders (anxiety, depression, and bipolar disorder) were strongly associated with PPCM during childbirth.
Most of the risk factors identified in the previous study were once against significantly associated with PPCM. Obesity was associated with a 1.7-fold elevated risk of PPCM while mood disorders nearly doubled the risk even when controlled for the previously identified risk factors.
“Obesity is a well known risk factor for heart failure including dilated cardiomyopathy via altered cardiac response to stress, abnormal thickening of the heart wall, abnormal use of energy by the heart, and several other factors.
“It is possible that the combination of obesity and pregnancy may put excessive stress on a heart that is less able to respond to stress and recovery from injury,” says Kao.
Moreover, mood disorders, particularly depression, are associated with increased risk of cardiovascular disease. Although there are several speculated mechanisms such as excess stress hormones (cortisol) or catecholamines (e.g. adrenaline), these have not been proven. Mood disorders may also be linked with behaviour changes in diet, sleep, activity, and prenatal care which could influence cardiac health, he explains.
Dr Kao continued, “Identifying high risk patients might provide an opportunity for earlier screening and potential treatment to slow progression and increase likelihood of recovery.
“For example, patients with relatively common pregnancy-related symptoms such as shortness of breath or leg swelling who also have five PPCM risk factors such as obesity, depression, age over 30, African ancestry and hypertension could be screened.”
He concluded, “We do not know if PPCM can be prevented, and scientists around the world are investigating therapies. Because almost all potential treatments may have some risk to the unborn child, treatment must only be initiated with convincing evidence of benefit to the mother and child. Therefore, our focus is on identifying very high risk populations to follow carefully with more dedicated testing.”
Source: European Society of Cardiology