A variety of factors can influence a lactating mother's milk supply. These factors include the mother's nutrition, hydration, stress levels, and overall health. The frequency and effectiveness of nursing sessions are crucial; the more the baby nurses, the more milk the body produces. Hormonal levels also play a significant role, particularly prolactin and oxytocin. Certain medical conditions, such as thyroid issues or polycystic ovary syndrome (PCOS), can also impact milk supply.