Nano brows, also known as nano needling or microblading, is a semi-permanent tattoo technique used to create the illusion of fuller, well-shaped eyebrows. It involves using a pen-like device with a small needle to deposit pigment into the skin. While it's a popular beauty treatment, there are several factors to consider if you're breastfeeding.

1. **Ink Absorption:** The body may absorb some of the pigment used in nano brows. While the amount is minimal, it's not clear if these pigments could pass into breast milk. Most professional-grade inks are non-toxic, but it's always best to discuss this with your technician before proceeding.

2. **Infection Risk:** Any procedure that breaks the skin carries a risk of infection. If an infection occurs, it could potentially affect your overall health and, by extension, your ability to breastfeed safely. Ensuring the procedure is done in a sterile environment by a certified professional can help mitigate this risk.

3. **Medications:** If a numbing cream or other medications are used during the procedure, you'll want to ensure they're safe for use while breastfeeding. Some drugs can pass into breast milk and may affect your baby.

4. **Stress and Discomfort:** The procedure can cause some discomfort and stress, which could potentially affect your milk supply. Everyone's response to pain is different, so it's hard to predict how your body might react.

5. **Healing Time:** Your body's resources are already working hard to produce milk and recover from childbirth. Adding the need to heal from a cosmetic procedure could put additional strain on your body.

Before proceeding with nano brows or any cosmetic procedure while breastfeeding, it's best to consult with your healthcare provider. They can provide personalized advice based on your health history and current situation. Remember, your health and your baby's health should always be the top priority.