When Sarah first saw her son, Gary, he was sheathed in bubblewrap, like a small parcel ready for the post. "I could hardly see him. He was all tubes and wires and had a bonnet on his head," Sarah says. "His arms and legs were wizened. He was like a fledgling that had fallen out of its nest."
Gary had arrived 15 weeks early and weighed only 2lb, the same as a bag of sugar. Doctors immediately put him on a ventilator, to enable him to breathe, but it was touch and go whether he would survive.
"When we went in each morning, we never knew what we were going to find," says Sarah, who visited every day with her husband, Neil, a social worker. "Tiny babies go up and down so easily. We could leave him in the evening quite well and the next morning find him extremely ill. Four other babies born at the same stage did not survive."
Gary suffered several lung collapses, a small brain haemorrhage and pneumonia. He had to have phototherapy (light treatment) for his jaundice, several courses of drugs and about 15 blood transfusions.
"Every time he got over one hurdle, another seemed to loom up. At the start I used to think that once he got off the ventilator, I could relax. But when he did, I became obsessed with the fact that he was still being given oxygen, from a head box.
"When I got him home, I felt he was a freak. It seemed strange that he was still alive. He was still attached by tubes to an oxygen cylinder and the health visitor had never dealt with such a baby before. Her weight chart, for checking babies' growth, did not allow for babies born at 25 weeks. It took me a long time to bond with him."
Gary is now a healthy 13-month-old, who weighs 20lb, can crawl and pull himself up on to his feet. But he has to have frequent developmental checks and regular brain scans. "It is much better than it was, but I still feel I cannot totally relax," says Sarah, who lives in Devon.
Every year, 52,500 mothers give birth to premature babies and go through some of the stresses and strains that Sarah suffered. One in 14 babies is born more than three weeks early and the rate has not changed in 20 years, according to the charity WellBeing. About 2,500 babies will weigh less than 4lb and require long-term intensive care in special units; 25,000 babies are born at less than 34 weeks, 7,500 at less than 32 weeks and 2,500 at less than 28 weeks.
Why is it not possible to reduce the premature baby rate? Prematurity is still the single largest cause of baby death, killing about 1,800 babies a year - 85 per cent of all deaths of normally formed babies in the first month of life. Is enough being done to discover the causes and take preventive action?
Today WellBeing, which was founded by the Royal College of Obstetricians and Gynaecologists, is holding a conference in London to consider these questions. "If we could find the causes, we would be some way to preventing premature births," says David Taylor, professor of obstetrics and gynaecology at Leicester University School of Medicine.
At present, doctors and midwives are able to hold up labour for only a relatively short time. Drugs known as tocolytics can usually postpone delivery for 24-48 hours - useful in allowing time to transfer a mother to a specialist centre, but not enough to produce a more mature baby.
"Some conditions associated with prematurity are known, such as pre-eclampsia (raised blood pressure), placental abruption (the placenta coming away from the side of the womb), growth retardation and multiple births. Doctors and scientists are trying to reduce the incidence of all these conditions," says Professor Taylor.
"But these only account for about half of all cases. Fifty per cent of women go into premature labour either because their membranes rupture or for unknown reasons.
"Finding a treatment that produces even a moderate effect on that group would have huge clinical benefit," Professor Taylor adds.
Doctors are exploring the theory that infection may play an important part in these cases. A massive investigation, involving 10,000 women in Britain, Australia, the Far and Middle East, called the Oracle trial, is investigating whether giving antibiotics to these women could postpone delivery and improve the health of the baby.
"We believe that some women with ruptured membranes, or who go into labour for no known reason, have a silent infection, which does not cause them any problem, but which causes labour.
"We are trying to find out whether, if you give antibiotics to them, you can curtail early labour and delivery. The women are randomly allocated into two groups, and one group is given an antibiotic and the other a placebo. The results will be analysed after every 1,000 cases, to see if there is an effect."
Another area that scientists are studying is whether administering the hormone progestogen to women at risk of having a premature baby could be effective in prolonging pregnancy. Evidence suggests that if the hormone is given regularly from the 12th week of pregnancy, it makes premature labour less likely. "The findings are encouraging enough to warrant further study," says Dr Iain Chalmers, author of A Guide to Effective Care in Pregnancy and Childbirth.
This treatment might have been useful in the case of 28-year-old Sarah. She knew, when she was pregnant with Gary, that she was at risk of a premature birth.
"Although my first pregnancy was normal and went to full-term, I lost my second baby at 22 weeks. This made me extremely nervous throughout my third pregnancy. On top of my own experience, my sister had also had a baby at 24 and a half weeks, who had only lived nine days. That was just a year before Gary was born.
"So when at the beginning of the 25th week of pregnancy, I started bleeding and my local hospital at Torbay said I was in labour and decided to transfer me to the regional centre, I went into a complete panic. I was only too well aware of the dangers."
Sarah feels she has never been given an adequate explanation of why she had two premature births. "There was a great difference between the obstetricians and paediatricians. The latter explained everything, but the obstetricians did not. It is as though until you lose two or three babies, they do not take the problem seriously.
"My body must be producing these babies prematurely for some reason, yet the doctors cannot find out why. My sister has also had two premature births and I can't help thinking this must be connected."
Sarah, who has received a great deal of information from Bliss, the charity for the newborn, added: "I find it very frustrating. We would like another baby, but I know I would be at risk again. We are lucky that Gary did not suffer any handicap, but next time, we might not be."
Professor Taylor says there is no evidence of a genetic tendency to produce premature babies, and admits that it is frustrating not only for women but also for doctors that the cause is often unknown. The prematurity rate has not changed significantly in the past 20 years, he explains, because "we do not know the causes of unexplained premature labour or some of the diseases associated with prematurity. So we do not have effective interventions to prevent either those arising from no apparent cause; or as a consequence of those diseases".
But, he says, the picture is not all gloom and doom. "The chances of survival have improved remarkably. In the Fifties, eight out of 10 very premature babies died; now eight out of 10 survive."
* Names have been changed.
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies