The review identified several notable associations:

Maternal obesity was associated with altered fatty acid profiles in breast milk (increased saturated fats, higher omega-6/omega-3 ratio, lower ALA/DHA levels), which potentially affect infant cognitive function and growth.
Adequate intakes of micronutrients like iodine and omega-3 fatty acids were associated with better infant neurodevelopment and reduced skin disease risks.
Supplementing with omega-3 fatty acids increased DHA/EPA levels in breast milk and was associated with improved neurological outcomes.
Iron intake was associated with better infant growth, whereas probiotics had mixed effects on immune markers and eczema risk.
Maternal smoking was associated with lower levels of osteopontin (a signaling protein) in breast milk, which may increase the risk of infections and autoimmune diseases in infants.

How does maternal lifestyle affect breast milk and infant health? Original paper