Study links obesity, mood disorders to greater risk of weakened heart during childbirth

New study finds the risk of peripartum cardiomyopathy - a weakened and enlarged heart - during childbirth may be raised for women who are obese or suffering from mood disorders, such as anxiety and depression

Women who are obese or who have mood disorders - such as anxiety and depression - may be almost twice as likely to have PPCM during childbirth.

Study author Dr. David Kao, assistant professor at the University of Colorado in Denver, and colleagues recently presented their findings at Heart Failure 2015 congress in Seville, Spain.

Peripartum cardiomyopathy (PPCM) is a rare heart disorder estimated to affect around 1 in 3,000-4,000 women annually in the US. Onset normally occurs in the final months of pregnancy up until 5 months after birth, and it is more common after the age of 30.

Though it is unclear exactly what causes PPCM, health care professionals believe it may be down to the extra blood that is pumped around the body during pregnancy, alongside other risk factors, such as high blood pressure and diabetes. In combination, these factors may put additional stress on the heart.

"Up to 70% of women recover fully with normal or near-normal heart function, " notes Dr. Kao, "but as many as 10-15% have persistent heart failure, sometimes requiring left ventricular assist device or heart transplantation. PPCM at the time of giving birth is associated with a four to five times higher rate of stillbirth."

For their study, Dr. Kao and colleagues set out to identify which women may be at higher risk of PPCM. "Identifying high-risk patients might provide an opportunity for earlier screening and potential treatment to slow progression and increase likelihood of recovery," says Dr. Kao.

Obesity, mood disorders almost double the risk of PPCM during childbirth

Previous research from the team involving 4 million mothers - 535 with PPCM during childbirth - identifiedanemia, high blood pressure, asthma, autoimmune disease, substance abuse, multiple gestations,preeclampsia and African ancestry as risk factors for PPCM during childbirth.

For this latest study, the researchers included the same set of mothers, alongside an additional 3.5 million mothers, of whom 486 had PPCM during childbirth. The hospital records of all women were analyzed.

As well as highlighting the previously identified risk factors for PPCM, the team identified some new ones -obesity and mood disorders.

They found that mothers who were obese were almost twice as likely to develop PPCM during childbirth as those of a normal weight, while mothers who had mood disorders - including anxiety, depression and bipolar disorder - had a 1.7 times higher risk for the condition than those without mood disorders.

Dr. Kao notes that both obesity and mood disorders have been associated with heart conditions. Combined with pregnancy, these factors could lead to increased strain on the heart, which may explain their findings.

He points out that obesity is linked to abnormal thickening of the heart wall, as well as a number of other problems. "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," he notes.

Mood disorders, Dr. Kao explains, may increase the risk of cardiovascular disease by raising levels of stress hormones, such as cortisol, though he notes the link has not been confirmed. "Mood disorders may also be linked with behavior changes in diet, sleep, activity and prenatal care which could influence cardiac health," he adds.

The team believes their findings may aid prevention and treatment of PPCM by helping to identify mothers at high risk for the condition. Dr. Kao adds:

"Because of PPCM's potentially devastating effects for mother and child, identifying patients at higher risk may allow us to follow them more carefully during pregnancy using indicators of worsening heart function like echocardiography, BNP [B-type natriuretic peptide], or troponin.

If there were signs that the mother's heart was weakening, we could potentially initiate treatment withbeta blockers and ACE inhibitors sooner to slow or prevent the development of PPCM, which would likely result in better outcomes."