It is important to take care of your breasts during pregnancy. They will get bigger and heavier and, as your breasts have only ligaments and no muscles, they could be stretched if they are not properly supported.
Most expectant mothers experience growing breasts well before a growing tummy and many outgrow their fashion bras early in pregnancy. There are no hard and fast rules but generally it is time to consider buying a maternity bra as soon as your fashion bra begins to feel uncomfortable.
Wearing a well designed maternity bra is the best way to support your breasts and preserve your shape. Due to the increased weight and tenderness of your breasts it should incorporate all of the following features.
Support
Wider straps, sides and underbust band. Firm elastic straps to eliminate 'bounce' and give you the extra support you need.
Coverage
More fabric over breast area. This will provide increased comfort as your breasts become more sensitive.
Adjustability
Adjustable to allow your bra to grow with you.
Comfort
They should have a high cotton content as your breasts will tend to perspire more and cotton will let your skin breathe.
