Women diagnosed with blood cancer during pregnancy face increased frequency of severe maternal morbidity and obstetric complications compared to women without a haematological malignancy, a study suggests.

The findings published in the Lancet Haematology [link here] have prompted the French researchers to stress the necessity for specialised care to manage the complex cases effectively.

The team conducted an observational nationwide cohort study of almost 10 million pregnancies in six million women in France between 2012 and 2022.

They identified 1366 pregnancy-associated haematological malignancies, of which 413 occurred during pregnancy (4.13 per 100,000 pregnancies) and 953 (9.53 per 100,000 pregnancies) within 12 months of the end of pregnancy (post-pregnancy).

Hodgkin lymphoma was the most common haematological malignancy during pregnancy (40%) followed by acute leukaemia (22%), aggressive B-cell non-Hodgkin lymphoma (12%) and myeloproliferative neoplasm (9%).

Pregnancy terminations increased when haematological malignancies were diagnosed during the first and second trimesters of pregnancy.

Findings showed no significant differences in overall survival between the haematological malignancy during and post-pregnancy groups across all types of haematological malignancy (IPW-adjusted hazard ratio [HR] 0.91), specifically for Hodgkin lymphoma (0.56), aggressive B-cell non-Hodgkin lymphoma (0.52), acute leukaemia (0.84) and natural killer-cell or T-cell non-Hodgkin lymphoma (0.78).

The most frequent maternal morbidities were pre-eclampsia (4.3% of 328 completed pregnancies in the haematological malignancy during pregnancy group vs 2.1% of 7,945,909 completed pregnancies in the no malignancy group), malnutrition (4% vs 1.1%), thrombosis (1.8% vs 0.2%) and infections (12.8% vs 8.1%).

Severe maternal morbidity was also more frequent in pregnant women with haematological malignancies than in those without (26% of 328 completed pregnancies vs 1.5% of 7,945,909 completed pregnancies; odds ratio 22.71).

The most common severe morbidities were transfusions of blood products (17.7% vs 0.4%), sepsis (6.4% vs 0.5%), acute respiratory distress syndrome (4.0% vs 0.1%), and disseminated intravascular coagulation (3.1% vs 0.2%).

Writing in an accompanying editorial [link here], Australian haematologists Dr Pietro Di Ciaccio and Dr Georgia Mills noted the overall prematurity rate of 45% for women diagnosed with haematological malignancy during their pregnancy.

“Preterm deliveries, whether spontaneous or induced, pose considerable risks of neonatal complications, including respiratory distress, infection, and admission to neonatal intensive care units,” said the Canberra and Sydney-based doctors.

“Importantly, the substantial weight of evidence suggests that the most critical determinant of neonatal wellbeing and normal neurocognitive outcomes is delivery at term, rather than exposure to chemotherapy in utero, at least after the first trimester. Nevertheless, there might be a tendency in clinical practice to induce labour early to expedite postpartum delivery of chemotherapy and reduce foetal exposure. This is probably misguided in most cases.”

Rates of spontaneous premature labour were also significantly higher in women diagnosed with haematological malignancy during pregnancy than in women without a diagnosis, they added. They said the impact of antenatal chemotherapy and disease biology on the rate was unclear but worthy of further exploration.