Bra producers have been forced to offer bigger cup sizes in China because improved nutrition means women are busting previous chest measurements.
China's underwear market is set to grow 20% a year over 10 years
The Beijing Institute of Clothing Technology said the average chest size of Chinese women had increased by nearly 1cm in the past decade.
Measurements were taken from nearly 3,000 women over six years.
In response, some underwear companies have created sub-brands specialising in larger bra sizes.
"It is so different from the past when most young women would wear A- or B-cup bras," Triumph brand saleswoman Zhang Jing told the Shanghai Daily.
The Hong Kong-based lingerie firm Embry Group no longer produces A-cups for larger chest circumferences and has increased production of C-, D- and E-cup bras to meet demand.
Embry opened special counters for its bigger-cup bras in February and is planning more outlets across the nation, the China Daily reported.
The clothing technology institute released a report last week saying the average chest circumference of Chinese women has risen by nearly 1cm to 83.53cm (32.89 inches) since the early 1990s.
This phenomenon, it said, was due to women eating more nutritiously and taking part in more sport.
Similar growth in the average height of children prompted a rethink last year in Beijing on the height allowance for free bus rides.