During pregnancy a woman's bra size can change often. Most expectant moms will grow out of their regular bras, some as early as the first trimester. That's because breast tissue is expanding with the production of milk ducts, and the circumference of the rib cage is also increasing.
The best way to ensure a comfortable fit and to promote healthy development is to get professionally measured by an in-store Fit Specialist every few months.
Nursing bras feature cups that can be easily moved for breastfeeding. These bras are also specifically designed to support your breasts when they're at their most sensitive.
To ensure the best possible fit, visit an in-store Fit Specialist no sooner than three weeks before delivery. Since your shape will continue to change up until the end of your pregnancy, premature measurements risk an inaccurate fitting.