BACKGROUND

Many young women with newly diagnosed breast cancer are interested in future pregnancies. Prospective data regarding fertility interest and reproductive patterns after diagnosis are needed to counsel patients.

METHODS

The Young Women's Breast Cancer Study is a multicenter, prospective cohort of women who were diagnosed with breast cancer at age ≤40 years between 2006 and 2016. Women complete surveys at baseline, every 6 months for 3 years, then annually. Here, the authors describe fertility interest and pregnancies within 5 years of diagnosis for women with stage 0 through III breast cancer.

RESULTS

Of 1026 eligible participants, 368 (36%) reported interest in future biologic children at least once within 5 years after diagnosis, including 16% at 5 years after diagnosis. Among 130 women who attempted to become pregnant, 90 (69.2%) conceived; and, among 896 women who did not attempt to conceive, 18 (2.0%) became pregnant, with a total of 152 pregnancies resulting in 91 live births. Factors associated with pregnancy included younger versus older age at diagnosis (aged ≤30 vs 36-40 years: odds ratio [OR], 6.63; 95% CI, 3.18-13.83; P < .0001; aged 31-35 vs 36-40 years: OR, 5.86; 95% CI, 3.37-10.17; P < .0001) and being nulliparous versus parous (OR, 2.66; 95% CI, 1.56-4.53; P = .001). The receipt of endocrine therapy versus no endocrine therapy (OR, 0.35; 95% CI, 0.20-0.59; P = .001) was inversely associated with pregnancy.

CONCLUSIONS

Many women remain interested in future fertility in the 4 years after a breast cancer diagnosis, indicating that longitudinal fertility discussions are needed. Although a minority of those interested in having children attempted to become pregnant in the first 5 years, most who attempted to conceive did so and had live births.