Severe maternal morbidity and risk of transplant rejection in pregnant patients with a history of solid-organ transplant

Abstract

Background

In 2023, 18,078 US women underwent solid organ transplants; over a third (n = 5547) were of reproductive age, receiving kidney (69.6%), liver (23.7%), or heart (9.0%) transplants. Successful pregnancies are feasible for transplant recipients, but these patients often face elevated pregnancy risks, including hypertension, gestational diabetes, pre-eclampsia, and preterm birth.

Objective

To determine rates of severe maternal morbidity (SMM) associated with prior kidney, liver, or heart transplant.

Study Design

This descriptive study was conducted using the TriNetX Research Network, a health research network with data from 95 health care organizations spanning 1/1/2010−10/29/2024. Patients aged 12-55 years were included if they underwent single solid organ transplant prior to pregnancy and had no prior history of transplant rejection. Pregnancy was defined by delivery CPT code indicating presence of a pregnancy. SMM was defined using Centers for Disease Control (CDC) ICD-10 codes for 21 indicators of SMM. The primary outcome was composite SMM during delivery hospitalization or within one year postpartum. Secondary outcomes included comparison of SMM in individuals with and without solid organ transplant history, as well as estimation of rates of individual indicators of SMM and postpartum transplant rejection over time.

Results

A total of 421 kidney, 192 liver, and 59 heart transplant recipients met inclusion criteria. Rates of composite SMM were greatest for heart transplant recipients (40.7%), with morbidity most often from pulmonary edema/acute heart failure (28.8%). This was followed by kidney transplant recipients (composite SMM 11.48%), with acute renal failure occurring in 9% of patients. Liver transplant recipients had the lowest composite SMM (7.48%). Rates of postpartum 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 (25.4%), followed by kidney (11.48%), and liver (7.48%).

Conclusion

Solid organ transplant recipients have significantly higher odds of composite SMM compared to pregnant non-transplant recipients. Among transplant recipients, patients with a history of heart transplant had the highest prevalence of composite non-transfusion SMM and highest rates of transplant rejection 5 years post-delivery. The impact of pregnancy on long-term outcomes in transplant recipients requires further study.