Neonatal outcomes of pregnancy-associated breast cancer: Population-based study on 11 million births

As the age at first pregnancy continues to rise in the United States so does the incidence of breast cancer diagnosed during pregnancy. Our objective was to evaluate temporal trends in the incidence of pregnancy-associated breast cancer (PABC) and to measure neonatal outcomes associated with PABC.

We conducted a population-based cohort study using the 1999-2012 Healthcare Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) from the United States. Logistic regression models, adjusted for maternal baseline characteristics, examined the effect of PABC on neonatal outcomes.

There were 11 846 300 deliveries between 1999 and 2012, of which 772 cases of PABC were identified, resulting in an overall incidence of 6.5 cases/100 000 pregnancies. There was a significant increase in the incidence of PABC during the study period (P < 0.05). Women with PABC tended to be older, of white ethnicity, belong to a higher income quartile and to be treated in an urban teaching hospital. In pregnancies complicated by breast cancer, there was a greater risk of preterm delivery (OR 4.84, 95% CI 4.05-5.79) and preterm premature rupture of membranes (OR 1.79, 95% CI 1.06-3.05). No associations were observed between PABC and intrauterine growth restriction, congenital anomalies or intrauterine fetal demise.

There is an uptrend in the incidence of PABC and therefore, the need for counseling these patients is also increasing. Although pregnancies with the diagnosis of maternal breast cancer are more prone to premature births, it is encouraging that these babies do not appear to be at increased risk for congenital anomalies, growth restriction, or fetal demise.