(977) Severe maternal morbidity and 5-year transplant rejection in pregnant patients with history of solid-organ transplant

To determine rates of severe maternal morbidity (SMM) and 5-year transplant rejection in pregnant patients with history of kidney, liver, or heart transplant.

Study Design: This descriptive study was conducted using the TriNetX Diamond Network, a health research network with data from 92 health care organizations from inception in 2009-8/2023.  Patients aged 12-55 years were included if they received a single solid organ transplant prior to pregnancy and had no prior history of transplant rejection. SMM was defined using Centers for Disease Control (CDC) ICD-10 codes for 21 indicators of SMM. The primary outcome was composite SMM. Secondary outcomes included rates of individual indicators of SMM and transplant rejection over time.

Results:

A total of 706 kidney, 321 liver, and 87 heart transplant recipients met inclusion criteria. Mean age at index was 31.8, 28.7, and 32.2 years for kidney, liver and heart transplant recipients, respectively. Baseline rates of comorbidities were different between cohorts (chronic hypertension: 52%, 16%, and 30% and diabetes mellitus: 14%, 8%, and 13% for kidney, liver, and heart, respectively). Rates of composite SMM were greatest for heart transplant recipients (35.63%), with morbidity most often from pulmonary edema/acute heart failure (26.43% (n=23)). This was followed by kidney transplant recipients (composite SMM: 17.99%), with acute renal failure occurring in 10.91% (n=77). Liver transplant recipients had the lowest composite SMM (12.15%). Rates of solid organ transplant rejection progressively increased at 1-, 2-, and 5-years post-delivery for all cohorts. Solid organ transplant rejection at 5-years was highest for heart transplant recipients (14.94%), followed by kidney (11.48%), and liver (7.48%).

Conclusion: Patients with history of heart transplant had highest composite SMM and highest rates of transplant rejection 5-years post-delivery. The potential impact of pregnancy on long-term outcomes in cardiac transplantation should be further explored.