Maternal hormonal contraception may pose a low but slightly elevated risk of non-lymphoid leukemia in children when used during or just prior to a pregnancy, a study published in Lancet Oncology has shown.
The prospective nationwide cohort study in Denmark used data from national registries on 1,185,157 births occurring from 1996 through 2014, cancer, and prescriptions to derive Cox proportional hazard ratios for leukemia risk in children included in the birth registry in association with mothers’ hormonal contraception use.
Maternal contraception use was divided into time periods of no use (never used), previous use (more than 3 months before pregnancy), and recent use (during or within the 3 months before the start of pregnancy). Some analyses considered use specifically during pregnancy.
Leukemia was diagnosed in 606 children in the study cohort: 465 cases of lymphoid leukemia and 141 cases of non-lymphoid leukemia. An increase in leukemia rates was seen among children of mothers who had recent use of hormonal contraception vs no use of hormonal contraception (HR 1.46; 95% CI, 1.09-1.96; P =.011).
A distinction between lymphoid and non-lymphoid leukemia risk was seen, with no association between maternal contraception use and lymphoid leukemia for either recent use (HR 1.27; 95% CI, 0.90-1.80; P =.167) or previous use (HR 1.23; 95% CI, 0.97-1.57; P =.089).
For non-lymphoid leukemia, however, risk was significantly higher with hormonal contraception use during pregnancy (HR 3.87; 95% CI, 1.48-10.15; P =.006) and with recent use overall (HR 2.17; 95% CI, 1.22-3.87; P =.008).
The authors noted that although non-lymphoid leukemia risk is increased for children of mothers who have used hormonal contraception, overall risk remains low. These study results, however, may be useful in informing decisions regarding hormonal contraception use.
Hargreave M, Mørch LS, Andersen KK, Winther JF, Schmiegelow K, Kjaer SK. Maternal use of hormonal contraception and risk of childhood leukaemia: a nationwide, population-based cohort study. Lancet Oncol. 2018;19(10):1307-1314.