Frequently Asked Questions Can I heat up my Avent Thermopads in the microwave? Philips Avent Thermopads help stimulate or sooth as you can use them both 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 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.