London, Dec 9 (IANS): Women who find that their bras do not fit have World War I to blame.

According to Sue McDonald, a bra fitting specialist, who has researched the undergarment's origins, bra sizes were developed from blouse sizes based on military uniforms during World War I.

The male military uniforms-based bra sizes from World War I have measurements that are no longer suitable for today's women, the Daily Mail reported.

"While women back then were typically slimmer and may have had boyish figures, the female shape today tends to be much fuller," Atul Khanna, a consultant plastic surgeon, was quoted as saying.

Nine in 10 women surveyed said their bra was painful and two in five said their bra was uncomfortable.

A third of women also had sore shoulders and a fifth of them suffered from back or neck pain, it was found.

An expert in breast health who carried out a research on bra measuring said the cup-sizing system during old days was never designed to go above a size D.

"Our research shows that as breasts get larger, the measuring system gets less accurate," Joanna Scurr from Portsmouth University was quoted as saying.