Bra sizing during pregnancy and postpartumUpdated a year ago

Both cup and band size will fluctuate during pregnancy and in the postpartum period. Each body is unique and there is no guideline to determine how much fluctuation any single individual will experience.

In general, most women will experience an increase in their band size due to position of the diaphragm moving up. This change will generally occur during the 2nd and 3rd trimester. Many customers may benefit from sizing up one band size from their pre-pregnancy bra size. In addition, cup size will generally start to increase towards the end of the 1st trimester and may continue to do so for the remainder of the pregnancy. 

During postpartum, there may be a rapid increase in cup size as breasts become engorged with milk production. The result may be an increase in 2 to 3 cup sizes, or more.