Haematological cancer in pregnancy in New South Wales, Australia: A population-based retrospective cohort study.

[BACKGROUND] Pregnancy-associated haematological cancers (PAHC) are rare but may have profound impacts on maternal and neonatal outcomes. We aimed to describe the incidence, survival rates, and perinatal outcomes associated with PAHC in New South Wales (NSW), Australia.

[METHODS] Utilising seven datasets, we performed a population-based retrospective cohort study, linking data for all women who gave birth in NSW from 1994 to 2013, and tracked mortality outcomes up to 2018. Women and their babies were stratified into three groups: gestational haematological cancer (HC), postpartum HC group, and pregnant women not diagnosed with cancer. Descriptive statistics, incidence, mortality rate, survival probability, and a composite severe maternal morbidity outcome indicator (MMOI) and composite neonatal adverse outcome indicator (NAOI) were calculated and compared between groups. We also conducted a sub-group analysis of women with lymphoma and leukaemia.

[FINDINGS] Of the 1786,302 pregnancies included in the cohort, 224 women were diagnosed with PAHC. The overall incidence of PAHC was 12.5/100,000 women giving birth, which increased by 4 % yearly over the study period. The overall mortality rate was 15.5/1000 and 20/1000 women-years in the gestational HC and postpartum HC groups, respectively. Gestational HCs were associated with higher odds of MMOI (AOR 17.39 (95 % CI: 9.88-30.59) and NAOI (AOR 4.69 (95 % CI: 2.43-9.03) compared to postpartum HC and pregnant women not diagnosed with cancer.

[INTERPRETATION] Over the two-decade study period, we observed a significant increase in the incidence of PAHCs, with an associated higher maternal and neonatal mortality and morbidity for women with gestational HCs. Our results emphasise the critical importance of decision-making and clinical practice regarding the continuation of pregnancy and cancer management for women diagnosed with PAHCs.