In-hospital supplementation and subsequent breastfeeding practices in Finland: A cross-sectional population-level study.

Our findings suggest that noncontrolled supplementation, without a trial's rigorous procedures of care, is associated with decreased breastfeeding postdischarge. Both donor milk and infant formula use were associated with lower breastfeeding rates, although the association was stronger with formula use. In clinical settings, liberal, nonmedically indicated supplementation should be avoided.