When Hilda Manson took a revolutionary drug to stop her miscarrying, she had no idea it would ruin her daughters' chances of having children. Julia Stuart hears their story

First there were the miscarriages. Then there was the trauma of her first son being stillborn, and her second dying within hours. When Hilda Manson found she was pregnant again, terrified of never having children, she followed medical advice while in the US and took a drug believed to prevent miscarriages. Such was her delight at giving birth to a daughter, she took the drug for her subsequent two pregnancies back in England. By her fourth, her UK doctor refused to prescribe it - but didn't tell her why.

In her London sitting room, Hilda, 78, looks at the photographs of her sons' children. She is worried the pictures might upset her two daughters. For Lesley and Claire have never been able to have children, as a result of the drug Hilda was prescribed. Floored by guilt, she has suffered severe depression. Her tears have been matched by those of her daughters, enraged that they had been robbed of fertility and motherhood.

DES (diethylstilbestrol) is known as the "silent Thalidomide". The synthetic oestrogen was developed in England in 1938. It wasn't patented and went on to be produced by more than 200 companies. It was prescribed to pregnant women in the UK between around 1950 and 1975, mainly to prevent miscarriage. This was despite the fact that research published in the American Journal of Obstetrics and Gynecology in 1953 revealed that women receiving DES suffered a higher rate of miscarriage.

There had been early warnings of its potential to harm. In 1940, a French medical journal reported that DES caused mammary tumours in male mice. The drug was used as a supplement to increase the size of livestock, but it was banned from chicken and lamb feed in the US in 1959 after high levels in meat caused male breast growth in humans.

DES was prescribed in the US to pregnant women from 1938 until 1971, when it was discovered that one in 1,000 daughters of women who had taken the drug developed a rare form of vaginal and cervical cancer, know as clear cell adenocarcinoma (CCAC). (There have been reports that it was given to pregnant women in Poland as late as 1991). All DES daughters carry a lifelong risk of CCAC and are 40 more times likely to develop it than unexposed women. Most cases have occurred in women in their late teens and early twenties.

But vaginal and cervical cancer is only one of a long list of side effects. Mothers and daughters have an increased risk of breast cancer (daughters aged over 40 have almost twice the usual risk of developing the disease). Studies have shown that up to a third of DES daughters were born with or developed some form of abnormality of the cervix, uterus or fallopian tubes, resulting in an increased risk of infertility, ectopic pregnancies, miscarriages and premature births. DES daughters are 50 per cent more likely to start the menopause early. Studies have shown that they have an increased risk of auto-immune diseases such as lupus and rheumatoid arthritis.

DES exposure can also affect men. The sons of women who took DES run a higher risk of genital problems, such as undescended or underdeveloped testicles, cysts on the back of the testes and lowered sperm count. There is also a possibility that the grandchildren of women who took the drug may be affected. Third-generation mice (offspring of DES daughter mice) have a higher rate of reproductive-organ tumours in later life.

It is thought that around 300,000 Britons, 300,000 people in Holland and five to 10 million Americans have been exposed to DES. While victims have been vocal in the US, and successfully sued for compensation, the tragedy remains largely unknown in the UK. Some British doctors have never heard of DES and there is only one dedicated clinic in Europe, based in Ireland. Some women may be unaware that their infertility is a result of their mother having taken the drug.

Lesley Benson, Hilda's eldest child, had her first internal examination at the age of 17. When she was 24, pre-cancerous and DES-effected cells were found on her cervix. At the age of 31, she had cervical laser treatment for both types of cells. "I had to do my own research as so little was known about DES," says Lesley, 55, a drama teacher from Bristol. "I got a lot of information from America."

A year after her treatment and still unable to conceive, she started fertility treatment. A post-coital test had showed that she produced little mucus and the sperm wasn't surviving as a result. It is a condition related to DES. "From then until 40, my second home was a hospital," says Lesley. "I was deeply depressed." The couple decided not to continue treatment. "I will never lose the grief of not having children and neither will my husband. It's very difficult to feel that one's body has been irrevocably affected by a drug.

"Even now, hormonal substances are being introduced into our environment that may be damaging people's reproductive health." Lesley is particularly concerned about oestrogens used in cattle feed, and the effects they could have on humans eating them. "I am outraged that this use of oestrogens is still going on; nobody is aware of the impact of the cocktails used. It took a generation for the damaging effects of DES to come to light."

Eighteen months ago, Lesley looked into whether she would be eligible for compensation in the US. But she discovered that cases cannot be brought in Massachusetts, where her mother was given the drug, if they precede 1953, when a particular piece of research about DES was available. Lesley was born in 1951.

Her sister, Claire Manson, a 53-year-old therapist who lives in London, started having smear tests at the age of 18 as a precaution. When she was about 34, she started to experience hot flushes and her periods stopped. Wanting to have children, she underwent 18 months of fertility treatment. Claire and her husband decided it was too distressing to continue. "I didn't want to be invaded any more," she says. "Going through fertility treatment and dealing with the impact of DES knocked me out. I felt bereft when we decided not to have any more treatment. Infertility hits in a place you don't know exists. It felt like I rendered my husband childless. We suffered terrible grief."

The couple decided to adopt, and were accepted, but changed their minds as they were still recovering from not being able to have their own children. The pain is still raw. She has decided against suing because she is unwilling to endure the invasive physical examination it would entail. Compensation relating to DES-exposure in the UK is extremely difficult. UK law requires action within three years of knowledge of the side effects and patients must know which of the 200-odd manufacturers produced the drug that their mother took.

"DES has had a huge effect on my life," says Claire. "I want policymakers and corporations to know that they damage an individual, they damage lives; that we were robbed."

Believing the drug had helped her produce two healthy babies, Hilda took it again while pregnant with her third child, Nicky. He later suffered from an undescended testicle, which was corrected. The 48-year-old now has two children. Andrew, her fourth child, is 41 and has three children.

While Lesley and Claire never blamed their mother, she felt enormous guilt. "I had a severe depression and went through treatment," she says. "My guilt as far as DES is concerned has now gone. I had a lot of help. It's been awful for the girls. We have very good relations, so it hasn't, in that sense, destroyed us."

DES Action UK, the support group, still hears from people who have only just learnt that they are affected. "Within the last couple of weeks, we had contact from someone who has had DES vaginal cancer," says Jane Kevan, a trustee of the charity. "DES seems to have been buried. Government figures say only three women in this country have been diagnosed with the vaginal cancer. We are aware of at least a dozen. We would like DES to be put back on to the medical training agenda so GPs and consultants know about it, and so people can get appropriate healthcare without fighting for it."

The facts about DES

DES daughters should receive annual DES examinations: smears taken from the vagina and cervix, colposcopy, a full pelvic examination and an iodine test to identify areas of adenosis, a type of tissue not usually found in the vagina.

In the UK, DES was known as stilboestrol and was sold under many brand names.

It was administered in tablet and injection form.

DES is now used to treat prostate cancer.

Progesterone treatments were also used to prevent miscarriage from the 1950s to the 1970s. They are not known to have any side-effects.

DES mothers and daughters should think carefully about HRT and the contraceptive pill. Some doctors are concerned about the cumulative effects of being exposed to oestrogen.

To determine whether you have been exposed to DES, speak to your mother or see her medical records. If it is not possible, potential DES daughters should ask for a referral for a full DES examination.

If your GP can't or won't refer you for a DES examination, contact the Royal College of Obstetricians and Gynaecology for advice.

DES daughters aged over 40 should consider annual breast checks.

For more information, visit www.des-action.org.uk