ASHARP pain in the back was the first sign something was wrong. The delight of finally becoming pregnant after seven years of trying had not worn off for Lisa Chamberlain. Confirmation the week before Christmas was present enough.
Yet the new year was to bring a terrible new discovery. Last Wednesday the former RSPCA worker and her partner attended hospital to track the cause of the mystery pain.
When nurses carried out an emergency scan they were disturbed by the grainy black and white image.
As Miss Chamberlain said: "They kept asking each other if they were babies who were close together – or 'something else'."
The emergency obstetrician eventually confirmed it was, indeed, "something else". Miss Chamberlain was pregnant with not one child, but "dicephalus twins", the rarest form of "Siamese twins", with two heads on one body and, crucially, only one heart, or so it appeared on the nine-week scan.
During the first fortnight after conception, when the fertilised embryo began to split into identical twins, the process had halted and as a result, the foetus was developing into a conjoined twin. The survival rate for such children is exceedingly low and once delivered many die within the first few days.
The policy in the NHS is for obstetricians and midwives to provide parents reeling with the discovery of a serious abnormality with "non-direct counselling". All the information of mortality rates and consequence for future child development is provided, but no direct advice is given, allowing the subject of an abortion to remain unspoken.
But there are severe circumstances in which doctors will deliberately raise the subject of a termination. The rare discovery of dicephalus twins is one such occasion.
Although advised to terminate the pregnancy, Miss Chamberlain, of Portsmouth, and her partner, Mike Pedace, who is a Catholic, decided to carry on, a decision they announced on the front page of the Sun yesterday, just six days after the diagnosis.
As she explained: "Some people might look at me and say: 'You're going to give birth to a freak – but I don't care because I feel blessed. To me, my twins are a gift from God and we're determined to give them their chance of life."
If successfully delivered, the babies will be the first dicephalus twins in British medical history. So are we moving into a bright future where the decision on whether to embrace or reject a severely disabled child is moving towards the side of life?
What is clear is that the post-natal world has become increasingly complicated since the days of previous generations who discovered their child's health upon birth. Only a fortnight ago it was announced that a child had been born through IVF and genetic screening that meant she was clear of a gene associated with breast cancer. In this "brave new world" are we both more vigilant against genetic abnormality and understanding too?
A recent report would suggest that the answer is yes. In November it was reported that the number of babies born with Down's Syndrome had increased since pre-natal screening was introduced in 1989. Yet the report failed to take into account the large increase in the number of Down's Syndrome babies conceived as more older women become pregnant.
As a result of the coverage the National Down Syndrome Cytogenetic Register was obliged to issue a thorough clarification. The published stories even managed to unite both the pro-life and pro-choice lobby who both agreed the figures painted an inaccurate picture.
The reality appears to be that nine out of ten antenatal diagnoses of Down's syndrome still end in termination.
Yet Professor Alan Cameron, a spokesman for the Royal College of Obstetricians and Gynaecologists, who is based at the Queen Mother's Hospital in Glasgow, believes that within the past ten years there has been a subtle change of attitude, with more couples opting to carry disabled children to term.
"The impression I have is that more couples are willing to go through with pregnancies where they did not in the past," he said. The example he cites is in the diagnosis of spina bifida where more children are being born.
"Ten years ago I would say that 90 per cent of couples would not go through with the pregnancy," he said.
The reason for the change, Prof Cameron believes, is the better care and understanding demonstrated by society.
"Parents recognise that there is now more opportunity for handicapped people. They now have a better quality of life. Many Down's Syndrome kids are going to mainstream schools. I think there has been an improvement in the health of the nation."
Jane Fisher, chairman of ARC, the charity for anti-natal results and choice, believes that every day prospective parents are faced with a difficult ethical dilemma.
"They are well aware that this is a much loved and much wanted child and they have to pause and think about what this will mean for them as a family and what it will mean for the child," she said.
"The difficulty is that they make the decision at a time when they are still reeling from the results. They do think about the long-term consequences of whatever decision they make – but it has to come down to the individual.
"In the case of the parents of the conjoined twins it will be very difficult because they have gone public and involved the media and it is still very early. They will now have the spotlight on them and although they appear to be very secure in their decision, we know from experience that this can change."
Yesterday Josephine Quintavalle, the organiser of Core Ethics, which comments on reproductive ethics, said she applauded the decision of Miss Chamberlain and said she deserved the nation's support.
"I think the right approach to abnormality is how we can provide as much help as possible to the baby and to the parents regardless of the type of disability," she said. "We cannot underestimate the terrible disappointment that parents will feel, but we can help them and their children. People are now talking about what we should do with autism. I think society grows in stature by the way it deals with the weakest members of society, not by its attempts to create a super-race."
However, Dr Ellie Lee, a senior lecturer in social policy and co-ordinator of the Pro-Choice Forum, took a more pragmatic approach to the problems the couple will now face. She said: "The family are going to need a tremendous amount of support. A Catholic faith may give you a certain clarity, but it is common sense to point out that they will have to undergo particular problems and psychological issues that are unique to the parents of a severely disabled child. The child will require constant care, if, that is, it survives and my understanding is that this is very unlikely."
Unlikely or not, the fate of Layla and Kelsey, as their parents have decided to name them, on the grounds that 75 per cent of Siamese twins are girls, remains in the balance.
The sisters with two hearts that beat as one
HOPE, for Lisa Chamberlain, is personified in the happy, gregarious form of Abigail and Brittany Hensel, from Minnesota. Now 18 they are one of only four dicephalus twins in the world to survive into their teens. It has been a battle against all the odds. One set of twins in every 40,000 are born connected, of which just 4 per cent have two heads but just one body.
When the Hensel twins were born their parents, Patty, a nurse and Mike, a carpenter, were warned that the babies were unlikely to survive the night. However, today they ride a bike, play the piano and gossip about boys. Like many twins they have very different personalities and tastes. Abigail is the feisty one, who likes orange juice for breakfast while Brittany is the joker of the family who will touch only milk.
They have two spines which join at the pelvis, two hearts, two oesophagi, two stomachs, three kidneys, two gall bladders, four lungs – two of which are joined – one liver, one ribcage, a shared circulatory system and partially shared nervous systems.
From the waist down all organs, including the intestine, bladder and reproductive organs, are shared.
The girls' parents have never considered having the twins separated, through fear that one or both might die or be left with such severe disabilities their quality of life would be compromised. However, Patty has since wondered if she made the right decision given the advances in medical techniques. Yet the consequences of separation would mean they would each have just one arm and one leg and be confined to a wheelchair.
Over the years the family has encouraged each girl's individuality even to the point of buying two seats for the cinema, though they only use one.
Each has her own separate meal and there are two birthday cakes with candles each year. If one of the twins misbehaves, their parents are careful to scold the individual responsible.
Yet the girls have benefited from the fact that each has her own heart, which, as far as the early nine-week scan can reveal, is not the case for Lisa Chamberlain's twins. As Professor Lewis Spitz, a British expert on conjoined twins said yesterday: "There would be greater risk of infection – and you'd have two heads controlling one side of the body's nervous impulses. I really can't see them surviving."