Frequently Asked Questions Can I heat up my Avent Thermopads in the microwave? Philips Avent Thermopads help to stimulate or to sooth, as you can use them either hot or cold. Find out how you should heat them to help stimulate your milk production. No microwave You cannot heat up the Thermopads in the microwave. It contains water which could start boiling, expanding the thermal pad. The microwave will not heat up evenly, creating hot spots. Heat up the Breast Pads for about 10 minutes in warm water: 50°C/122°F. Do not boil the warm water.