Campaigners are calling for government action after a record number of 14 women took their lives in prisons across England and Wales in 2003.
A record 14 women inmates killed themselves in 2003
The Howard League for Penal Reform, which published the figures on Tuesday, says it is a "shameful" situation that is only likely to get worse.
The charity is now urging ministers to reduce the numbers of prisoners - particularly female - behind bars.
The Prison Service says staff have saved a significant number of lives.
The numbers of self inflicted deaths by men and women in custody was 94 in 2003, compared with 95 the previous year, according to the Prison Service.
Among the 94 in 2003 were 14 women - five more than in 2002 and eight more than in 2001.
Claire McCarthy, the League's policy and campaigns officer, told BBC News Online: "As a proportion of the prison population, women are 4 to 5%, yet the proportion of those committing suicide is 15%.
"We think, in particular, prison over-crowding is the problem and the women's prison population continued to rise in 2003.
"The women's prisons are at complete bursting point. They are suffering staff shortages as well so that compounds the problem.
"We believe sentencing for women is increasingly inappropriate. Several of the 14 who died were young women, non violent, drug takers and primary carers of children and vulnerable to suicide.
"Women with children and drug problems could be better dealt with in the community with no loss of life."
According to the League, the female prison population topped 4,400 in 2003, up on 4,200 in 2002.
The prisons' ombudsman is investigating Styal Prison in Wilmslow, Cheshire, which has seen the most suicides of all women's jails - six deaths between summer 2002 and summer 2003.
FEMALE PRISONER DEATHS IN ENGLAND AND WALES:
2003 - 14
2002 - 9
2001 - 6
2000 - 8
"Women's prisons replace half of their population every month," said Ms McCarthy. "It is very difficult to detect who is at risk of suicide because staff don't get enough time to get to know the women to detect an increased risk.
"Styal is supposed to hold 417 female prisoners and is routinely holding up to 450. An extra 30 odd prisoners in a small prison has quite an impact."
A Prison Service spokesman agreed that the numbers of women prisoner deaths have been "rising significantly".
"The increase is partly explained by the increase in the female [prison] population which has more than doubled since the early 1990s," he said.
The spokesman said sentencing issues were "a matter for the courts".
But he insisted the Prison Service targeted its efforts on prisons "where the risks are highest, particularly during the crucial early period of custody".
The spokesman said from April 2003 until 5 January 2004, 64 men and women prisoners took their lives, compared to 76 at the same stage in the previous financial year.
"The previous rate of self inflicted deaths this year is 129 per 100,000 prisoners compared to 133 in 2002 and is lower than the peak rate of 140 in 1999," he said.
"Significant numbers of lives have been saved in recent years as a result of prompt actions by staff.
"The number of prisoners resuscitated following self harm incidents has risen over the past three years up to 197 in 2003."
The spokesman said current Prison Service practises and procedures were being "reviewed" in consultation with a wide range of interested groups.
The prisons minister will be announcing the "next steps and approaches" in the spring.
'Duty of care'
Pauline Campbell, whose 18-year-old daughter Sarah died in Styal Prison in January 2003, said the numbers of women inmates taking their lives was "unacceptable" and reminded the government of its legal duty of care for prisoners.
The League survey found that five prisons experienced more than four deaths during 2003, including five at Blakenhurst in Worcestershire, and four in each at Birmingham, Nottingham, Winchester and Styal.