At least according to this NYT article. There is also some comparative information including the claim that women are not shackled during childbirth in Chinese prisons, and this:
In the United States and in China, women now account for about 9 percent and 6 percent of inmates, respectively, Mr. Kamm estimated. Fast-paced social change and urbanization are factors in China, with Ms. Wang estimating that about 70 percent of women in Chinese prisons are “secondary criminals” who have aided men in crimes like trafficking in women and children or organizing prostitution. Domestic violence is also a major reason for women’s incarceration, both said.
“As tension in society grows, and it really is growing, men take it out on the women,” said Mr. Kamm, adding that increasingly, women were fighting back.
In the United States, narcotics offenses are a leading cause of female imprisonment, he said.
