Two weeks after Bakhor came home with her newborn son the joy of the new baby was overshadowed by a growing suspicion that something had gone badly wrong.

"I kept bleeding heavy black lumps, and the pain was unbearable, I thought I had a tumour," the 32-year-old Uzbek says.

It took Bakhor four months to save up money for an ultrasound. She cries as she remembers the result. During the caesarean section, the doctor explained, she had a hysterectomy.

"The doctor said 'you don't have a uterus any more'. He said: 'What do you need it for? Two children is enough for you'," she says.

A two-month long investigation for the BBC World Service and Radio 4 has uncovered what appears to be a systematic state-run programme in Uzbekistan to sterilise women, often against their will and without their knowledge.

Uzbek president Islam Karimov tolerates no dissent in his country and women and doctors who told their stories did so on condition of anonymity. Over secure phone lines doctors and health ministry officials told me that while first recorded cases of forced sterilisations go back to 2004, in 2009 sterilisations became a state policy. "All of us have a sterilization quota," said a gynaecologist in the capital, Tashkent. "My quota is four women a month. We are under a lot of pressure." In rural areas, doctors say, the number can be as high as eight women a week.

"We go from house to house convincing women to have the operation," said a chief surgeon in a rural hospital. "It's easy to talk a poor woman into it. It's also easy to trick them," he admitted.

Several doctors said that in the last two years there had been a dramatic increase in caesarean sections across the country, disputing official statements that only 6.8% of women give birth that way. "I believe 80% of women give birth through c-sections. This makes it very easy to tie the fallopian tubes," said one gynaecologist.

Doctors believe the programme is meant to keep Uzbekistan's growing population under control, although some suggest it is also a bizarre short-cut to lowering maternal and infant mortality rates.

"It's a simple formula – fewer women give birth, fewer of them die," said one surgeon, explaining that this helps the country to achieve a better ranking internationally.

In a written statement the Uzbek government said allegations of a forced sterilisation programme "have nothing to do with reality" and that the "surgical contraception is carried out only on a voluntary basis after consultation with a specialist and with the written consent of both spouses. Uzbekistan's record in protecting mothers and babies is excellent and could be considered a model for countries around the world," the letter says.

But on Friday the Avaaz pressure group called on US secretary of state Hillary Clinton to take the scandal up with Karimov. Noting the recent diplomatic rapprochement between Washington and Tashkent, which the US relies on as a conduit to supply troops in Afghanistan, Avaaz said it was time for Clinton to "cut him off".

Karimov, it said, was "propped up by millions of dollars from the US government who pay him for military transport across the country. This latest round of brutality, this time against his country's women, has turned on the global spotlight."

Many observers believe maternal and infant health is one field in which the Uzbek government has managed to hang on to international legitimacy. Karimov labelled 2012 as "The year of the family"

"Amidst its otherwise abysmal rights record, the Uzbek government has been successful in persuading the west that it is willing to have a limited UN presence in the country to run programmes it perceives to be both apolitical and non-threatening," said Steve Swerdlow of Human Rights Watch

"One of these has been to allow programmes on the promotion of maternal and infant health. But these reports of forced sterilization seriously undermine any claim that Tashkent is willing to genuinely engage even on these issues." says Steve Swerdlow of Human Rights Watch.

Among many recordings we smuggled out of the country by a courier, there is a testimony of a young woman who describes how in 2011 she gave birth to a baby girl through an emergency caesarean. The following day she was told she had been sterilised. There is a long pause and then the woman's voice breaks into tears. "My baby," she says, "my only child, died later that day."

Natalia Antelava is a Delhi-based reporter for the BBC