Today, breastfeeding can be continued after you go back to work. Milk can be pumped using a breast pump and kept in a fridge or freezer.
However, it is recommended not to start pumping milk before your baby is 4 weeks old. At that time, your milk production is well established and the baby knows how to feed as he/she should. The best time to pump milk is in the morning; milk production is more active then.
It is not recommended using a microwave to defrost as it changes the nutritional quality of milk. The best method is to let it defrost in a fridge or under cold running water.
Once defrosted, the milk must be kept in the fridge and used within 24 hours or discarded.