Test your new pumping bra for fit while pumping

Put on a comfortable bra. It should not be a padded or breast-minimizing bra or you won't get a correct size.

Hold one end of the tape measure to the breast cheap lingerie bone above your breasts. Wrap it under your arms and across your back until it reaches the starting point on your breast bone. Write the number down; this is your band size.

Mark an "X" where each of your nipples are and take off the bra.
Make a small cut in the shape of each "X" that you have drawn. The cuts should be small at first.

Slide the small end of one of your breast shield (the horn-shaped piece of your pump that sits against your breast when pumping; may also be called a flange) through the hole you've just cut. If it won't fit, make the cut gradually larger until you can fit the piece through the hole. It should slide through, but not easily.

Test your new pumping bra for fit while pumping. The bra should hold the breast shields firmly against your breasts as you pump, not allowing any air through and not breaking suction.

Measure frame size. Using the tape measure, measure the diameter around the chest, directly below the breasts, in inches. Record this measurement to the nearest inch on paper.

Measure breast size. Using the tape measure, measure around the diameter of the bust line. Place the tape measure over the fullest part of the breast. Do not press down on the breast, but make sure the tape measure rests comfortably on the breasts. Record this measurement to the nearest inch on paper.

Place the pre-fitted bra cups on a flat working surface. If you are adding underwire to a preexisting bra, lay the bra down flat.

Place the wire at the bottom of the bra cups. Shape the wire so that it curves with the natural curvature of the cups. Bras are not meant to be straight across at the bottom. Cut the wire to the appropriate size of the cups.