Pregnancy and long-term outcomes of female patients with chronic myeloid leukemia on tyrosine kinase inhibitors who experienced unplanned pregnancies

Purpose: Despite the general recommendation to avoid Tyrosine Kinase Inhibitors (TKIs) for Chronic Myeloid Leukemia (CML) during pregnancy, unplanned pregnancies still occur, particularly among female patients residing in low- and middle-income countries (LMICs). We aimed to investigate the outcomes of pregnancy, foetal development, and disease progression among female CML patients in chronic phase (CML-CP) undergoing TKI therapy who encountered unplanned pregnancies in a tertiary care hospital in northern India. Methods: We conducted a retrospective analysis of all pregnancies in female CML-CP between January 2002 and December 2022 at our hospital. Patients were included if they had a confirmed diagnosis of CML-CP, were receiving TKI therapy during conception, and had available medical records. We analysed the data on pregnancy outcomes, foetal development, and disease progression through a review of medical records. Results: We identified 36 pregnancies in female CML-CP patients on TKI therapy during the study period, with 33 (91.7%) being unplanned. Sixteen pregnancies (48.5%) were conceived at less than major molecular remission (MMR) status. Twelve pregnancies (36.4%) were electively terminated, 4 (12.1%) had miscarriages, and, 17 (51.5%) pregnancies resulted in childbirth. Out of the 17 childbirths, 10 were full-term deliveries, and 7 were preterm deliveries. Twin pregnancies had a high incidence (18.2%). Among the 21 pregnancies that were not electively terminated, TKI was stopped at the first pregnancy detection in 14 pregnancies, while imatinib was continued throughout 7 pregnancies. Patients who discontinued TKI had a higher but statistically non-significant incidence of adverse pregnancy outcomes compared to those who continued imatinib throughout pregnancy (64.2% vs. 28.6%, p = 0.18). Additionally, the risk of long-term disease progression among patients who discontinued TKI during pregnancy and those who continued imatinib throughout pregnancy was 21.4% and 16.7% (p = 0.9), respectively. The risk of long-term disease progression was significantly increased in those persistently at less than MMR pre- and post-gestation (p = 0.0002). Conclusion: Our findings suggest that continuing imatinib therapy during pregnancy, may be a reasonable option for CML patients residing in low- and middle-income countries to reduce the risk of disease progression and adverse pregnancy outcomes. Patients persistently at less than MMR levels pre- and post-gestation should be