Can raised oestrogen cause breasts to leak when not pregnant?

Yes, elevated estrogen levels can lead to breast tissue changes that may cause leakage or discharge from the nipples, even when not pregnant. This condition, known as galactorrhea, can occur due to hormonal imbalances or other factors like certain medications, stress, or underlying health conditions. If someone experiences unexpected breast leakage, it's important to consult a healthcare professional for evaluation and appropriate management.