Heart transplant recipients who become pregnant face higher risk of pregnancy complications, and their infants risk lower birthweights and inheritance of cardiac anomalies. Also concerning, self-reported data from the Transplant Patient Registry International (TPR) show that nearly half of these pregnancies are unplanned.
These are some of the findings from an analysis in The Journal of Heart and Lung Transplantation by Lynn R. Punnoose, M.D., associate director of the Advanced Heart Failure/Transplant Fellowship Program at Vanderbilt University Medical Center.
“We are transplanting younger patients, and many are surviving to reproductive age,” Punnoose said. “This study points to the need for all of us to be more intentional in counseling these patients pre-transplant, when possible, and certainly post-transplant.”
“This study points to the need for all of us to be more intentional in counseling these patients pre-transplant, when possible, and certainly post-transplant.”
Eyeing the Pregnancy Crucible
Punnoose and colleagues studied the 1987-2016 records of 91 female heart transplant recipients with pregnancies who enrolled in the voluntary TPR. A total of 157 pregnancies were reported, with an average span from transplant to conception of 7 ± 6.1 years. “No other study has been large enough to clarify the potential hazards of the elevated hemodynamic load of pregnancy, or of recurrent graft dysfunction in women with a history of peripartum cardiomyopathy,” Punnoose said.
Overall heightened risks for pregnant mothers with transplanted hearts included hypertension, pre-eclampsia, diabetes, infection and graft rejection. A total of 69 percent of pregnancies were successful and no infant deaths were reported. However, 41 percent of live births were preterm, and 37 percent of live births had below-average birthweights. Seven infants inherited cardiac conditions.
A total of 20 percent of patients were exposed to mycophenolic acid (MPA), a teratogenic agent linked to aural atresia, facial clefts, and anomalies of the cardiac, skeletal and tracheoesophageal system. While miscarriages occurred in 26 percent of all pregnancies reported, miscarriages occurred in 63 percent of pregnancies exposed to MPA.
Planning and Surveillance
As registry numbers accrue, Punnoose plans to do survival analyses to further clarify the risks of one or more pregnancies. “We need to look at these women’s immunological changes after pregnancy, and at graft function (ejection fraction) post-transplant to see if their hearts are compromised by the pregnancy,” she said.
In some cases, prospects for women with heart transplants who become pregnant may be improved by regular sonographic surveillance. Recommended interventions include changes in immunosuppressant regimens, with avoidance of MPA being vitally important. “Women on MPA need to switch to other immunosuppressant therapy if they may become pregnant,” Punnoose said.
Punnoose says the study findings strengthen the case for counseling. “Often the patient is not well enough to have this discussion just prior to transplant, or they are still quite young. Along the way, though, the cardiologist, the transplant surgeon and the gynecologist need to have these discussions and educate the patient on the risks of pregnancy,” she said.
For some women, this starts with understanding the condition that led to their transplant. “Familial heart disease constitutes seven percent of heart transplant indications,” Punnoose said. “These women need to know they have a heritable condition and the odds of passing on the defect.”
“These women need to know they have a heritable condition and the odds of passing on the defect.”
Patients also need to understand that the top threats transplant pose to their own survival – rejection, cardiac allograft vasculopathy, and cardiac arrest – are heightened by pregnancy and impact the child.
“I hope this research and our follow-up will lead to more women making well-informed, deliberate decisions,” Punnoose said.