Severe Maternal Morbidity and Maternal Mortality Associated with Pregnancies Among Women With Solid Organ Transplants

Solid organ transplants (SOT), including kidney, liver, heart, lung, and pancreas transplants, have become more common in the last few decades. However, few population-based studies have attempted to comprehensively quantify severe maternal morbidity (SMM) and maternal mortality associated with pregnancies among recipients of SOTs. This study aimed to determine the proportion of women with SOTs among all delivering women, and to quantify the rates of SMM and maternal mortality associated with SOT.

We conducted a retrospective cohort study of all hospital deliveries at ≥20⁰ weeks gestation in Canada (excluding Québec) from April 2003 to March 2018. SMM was defined using a standard list of SMM conditions. Logistic regression provided adjusted ORs (AORs) for associations between SOT and SMM/maternal mortality, adjusting for age, parity, plurality, and other confounders.

Among the 4, 157 547 women who delivered during the study period, 342 had an SOT (63% kidney, 25% liver transplant). The composite SMM rate was significantly higher in the SOT group than in the non-SOT group (134.5 vs. 9.97 per 1000 deliveries; unadjusted odds ratio 13.5; 95% CI 10.1-18.0, AOR 10.8; 95% CI 7.60-15.3). Women with SOT had higher rates of specific SMM types, including severe preeclampsia (AOR 8.29; 95% CI 2.99-23.0), eclampsia (AOR 10.8; 95% CI 3.42-34.1), acute renal failure (AOR 93.9; 95% CI 58.3-151.2), acute fatty liver with transfusion (AOR 21.3; 95% CI 2.89-157.8), hepatic failure (AOR 91.4; 95% CI 11.6-722.4), cardiac conditions (AOR 7.52; 95% CI 2.72-20.8), and other SMM. The median hospital stay was 8 versus 3 days for women with and without SOT, respectively; the proportion with prolonged stay (≥7 days) was 22.3% versus 1.78% (rate ratio 12.5; 95% CI 9.84-16.0).

Prolonged hospitalization and elevated severe morbidity rates highlight the substantial clinical risk associated with deliveries to women who have had an SOT.