Maternal and obstetric outcomes in women with pregnancy-associated haematological malignancies: an observational nationwide cohort study

Pregnancy-associated haematological malignancy is a rare event; therefore, data available to guide the treatment are scarce. We aimed to evaluate the incidence, overall survival, and maternal morbidity and mortality of women with pregnancy-associated haematological malignancies. We conducted a nationwide observational cohort study using the French National Healthcare Data System (SNDS), a health-care administrative database covering up to 99% of the French population. We included all pregnancies in France ending between Jan 1, 2012, and Dec 31, 2022. Pregnancies with terminations or miscarriages managed on an outpatient basis, and women with a history of haematological malignancies before pregnancy were excluded. A Cox proportional hazards model was used to assess overall survival, defined as the date of haematological malignancy diagnosis to either death or the end of the study follow-up, in the haematological malignancy during pregnancy group (pregnancies with a diagnosis of haematological malignancy during pregnancy) compared with the haematological malignancy post-pregnancy group (pregnancies with a diagnosis of haematological malignancy in the year following pregnancy). Severe maternal morbidity was compared in the haematological malignancy during pregnancy group versus the reference group (pregnancies without a history of haematological malignancy or a diagnosis of pregnancy-associated haematological malignancy). Births were classified as very preterm (