Introduction/Background To evaluate obstetric and neonatal outcomes of the first live birth conceived following breast cancer diagnosis.

Methodology We performed a population-based study to compare live births between women with a history of breast cancer and matched controls with no cancer history. Cases and controls were identified using linked data from the California Cancer Registry and California Office of Statewide Health Planning and Development datasets. Cases were diagnosed with stage I-III breast cancer at ages 18–45 years between January 1, 2000, and December 31, 2012, and conceived ≥12 months after breast cancer diagnosis. Controls were covariate-matched women without a history of breast cancer who delivered during 2000–2012. The primary outcome was preterm birth <37 weeks. Secondary outcomes were preterm birth <32 weeks, small for gestational age, cesarean delivery, severe maternal morbidity, and neonatal morbidity. Subgroup analyses were used to assess time from initial treatment to conception and receipt of additional adjuvant therapy prior to pregnancy on outcomes of interest.

Results Of 30,021 women age 18–45 diagnosed with stage I-III breast cancer during 2000–2012, 553 met the study inclusion criteria. Those with a history of breast cancer and matched controls had similar odds of preterm birth <37 weeks (odds ratio [OR], 1.29; 95% CI, 0.95–1.74), preterm birth <32 weeks (OR, 0.77; 95% CI, 0.34–1.79), delivering a small for gestational age neonate (<5th percentile: OR, 0.60; 95% CI, 0.35–1.03; <10th percentile: OR, 0.94; 95% CI, 0.68–1.30), and experiencing severe maternal morbidity (OR, 1.61; 95% CI, 0.74–3.50). Patients with a history of breast cancer had higher odds of undergoing a cesarean delivery (OR, 1.25; 95% CI, 1.03–1.53), however their offspring did not have increased odds of neonatal morbidity compared to controls (OR, 1.15; 95% CI, 0.81–1.62).

Conclusion Breast cancer history was not strongly associated with obstetric and neonatal complications.