By Robert Pigott
BBC, Sierra Leone
When Fatmata Kargbo became pregnant in her late teens she had only a vague idea of the risks of childbirth in Sierra Leone.
Rejected by her family, Fatmata lives and works alone
In a country with the highest maternal mortality in the world - about 2% of women die in childbirth - she knew there were dangers.
But she was completely unaware of another far more secret risk - until her own prolonged labour left her with a dead baby and permanent incontinence.
It is estimated that every year there are 5,000 new cases of fistula, called vesico-vaginal fistula (VVF) by doctors, just in this small African country.
It happens because - as in Fatmata's case - women have little or no access to expert ante-natal or obstetric care.
Like her, they often have children before their bodies are fully developed, and, when something goes wrong, the advice they receive is often disastrously misguided.
Most commonly the head of the foetus is too large to enter the birth canal, and presses the bladder against the bony side wall of the pelvis.
Crushed in that way over a period of days, the tissue dies and a hole is created.
From that moment the women are never free of the trickle of urine.
Fatmata's experience was as typical as it was catastrophic.
She was rejected by her husband, and by her family.
Regarded as unclean - and by some as jinxed - she was driven out of her village.
Fistula surgery costs $180, but many women live with life-long incontinence
She is now to be found on a bleak stretch of ground on the edge of the capital Freetown, breaking stones for builders.
No-one will work with her, so day after day she sits in the sun pounding stones with a hammer.
She's been incontinent for 10 years, and expects it to be a life sentence.
"Everyone deserted me - my husband deserted me, my friends deserted me. I know I will never have a husband, I will never have a boyfriend, I will never have a baby. So I just live by myself," she says unemotionally.
Fatmata's home is a corrugated iron shack, about 10 feet square, containing some clothes, an oil lamp and a mattress.
By the mattress, on an upturned mirror she has saved a single cigarette.
It is hard to exaggerate the misery of life-long incontinence in a society too poor for any real remedy, and in which the victims are so thoroughly cast out.
Ian McColl, former head surgeon at Guy's Hospital in London, gives his time to surgery correcting such conditions aboard the floating hospital belonging to the Christian charity Mercy Ships.
Their ship, Anastasis, has just spent several months moored in Freetown harbour.
Sia gave birth when she was 10, which made her incontinent
"The women realise that if they drink less they will leak less, so they become dehydrated and are then susceptible to infections," says Dr McColl.
"If they don't die of that, they may find the whole thing completely intolerable, and take their own lives. We're not sure about how many do this, but we keep hearing about it, and in terms of the numbers of people with this condition, it may well be that tens of thousands of them are committing suicide".
The Anastasis - with its three modern operating rooms - has been able to repair fewer than a hundred fistulas during its visit, as well as treating numerous other conditions such as cataracts and cleft palates.
It is also trying to train local midwives, to stem the annual tide of new cases.
Mercy Ships' head midwife, Elizabeth Hunter, is pessimistic about a solution to what she says is a scourge affecting most of the developing world.
It costs only about $180 to carry out fistula surgery, but Elizabeth Hunter says that at the present rate it would take 50 years to repair just the existing cases.
Elizabeth Hunter says young women - often in their early teens - come under intense pressure to have their babies without the expense of medical help.
Families will often press down on the abdomen of pregnant women in an attempt to expel a foetus.
"We just can't imagine the misery of these women, but it's going to be an ongoing misery for the next, perhaps 100 years, perhaps more. I can't see an ending to it," she says.
A few weeks ago the last of the women whose fistulas were repaired by Mercy Ships returned home to a remote eastern province.
They included 15-year-old Sia Foday who was married off by her family at the age of nine and was quickly pregnant.
Sia - small for her age - was only 10 when she tried to give birth and ended up incontinent.
Another of the women, Aminata Kanda, said she only survived because her children collected firewood to sell and helped her tend a small garden.
"Life was really horrible for me. When I was in this sickness the urine was coming non-stop... the odour of the urine is horrible... that is why even my husband wouldn't allow me to stay in his house," she says.
Were it not for Mercy Ships both women would probably have had to live with the condition forever.
United Nations agencies have sounded what they call a "global alarm" about this medical disaster.
In the West - on the rare occasions it occurs - fistula is curable.
But in the developing world it has condemned uncounted millions of women to lives of solitude, poverty and despair.