Fit Problem: Underwire pokes or sits on tissue

The short answer: The wire is too narrow for your root width, or the cup is too small so the wire rests on breast tissue. Go up a cup letter, or choose styles with wider, shallower wires. All breast tissue must sit inside the wire line.

A wire that pokes at the underarm, stabs at the center or presses on breast tissue is a wire in the wrong place, and where it pokes names the cause. Side poking means the wire is too wide or too tall for your frame, standing past your tissue into your arm's path. Center digging usually means cups too small, forcing the wire to sit on the slope of tissue instead of the soft fold beneath it.

The anatomical rule: all breast tissue lives inside the wire. Trace where your tissue naturally folds at the bottom and side; the wire should follow that crease exactly, touching ribs, never breast. If your measured size pokes in every brand, your root width differs from the average block: narrow-wire brands (many Polish and Japanese makers) or wide-wire brands (many UK full-bust houses) cut for different roots, and switching families fixes what letters cannot.

A wire that suddenly pokes in a bra that used to behave has probably escaped its casing or bent in the wash; that is retirement, not resizing. Hand-wash or bag underwires, never tumble-dry, and the wires keep their shape for the band's full lifespan.