Midwifery- The Social Context of Childbirth. Antenatal Screening for Down's syndrome
Introduction
Having a baby with Down's syndrome (DS) is distressing for the parents, and commits them to a higher input of care than they were expecting for the rest of their, or the child's life. Down's syndrome children are more likely to have other health problems, as well as social and educational disadvantages.
There is evidence in ancient art of people with trisomy 21 being part of the human race for thousands of years but it was not until 1866 that Dr John Langdon Down first remarked on the facial similarities of a group of his mentally retarded patients. Unfortunately, he used racial descriptors such as "mongol" to describe their appearance which led to a century of inaccurate and misleading terminology. People who have Down syndrome and their advocates are understandably sensitive about the words used to describe this chromosomal condition. With the identification of the chromosomal basis of Down syndrome in 1959, a gradual process of acceptance of trisomy 21 as being a variation of normal has done a lot to remove some of the handicap and end uninformed debates over the "humanity" of people with Down syndrome (Copel and Singh, 1999).
Down syndrome is the commonest identifiable cause of intellectual disability, accounting for almost one third of cases. It occurs equally in all races with an overall incidence of approximately 1 in 800 births. This is much lower than the actual conception rate due to a high incidence of spontaneous and surgical abortion. The increase in incidence with advancing maternal age is well-known but what is not commonly realized is that most children with Down syndrome are born to mothers who are less than 30. This is due to a greater number of pregnancies in this age group compared to the older group.
People with Down syndrome are part of our community and as such are part of the patient population. While there are some medical conditions which are more common in people with an extra chromosome 21, there is nothing which is unique to this group or which is totally outside the scope of general practitioner involvement. The key to good quality care is to be familiar with the syndrome but, more importantly, to know the person who has the syndrome.
The advocacy efforts of people with Down syndrome and their families have resulted in huge improvements in life quality and expectancy (Trumble, 1993). The medical profession is attempting to match these developments by becoming more sophisticated in its approach to ethical issues, more energetic in its provision of care and more cooperative in its interactions with people who have Down syndrome and their families.
What is Down's syndrome?
Children with Down Syndrome (DS) account for one of every 800 births. The risk of chromosome disorders like DS, trisomy 13, and trisomy 18 increases with maternal age. The incidence of DS at birth is lower at age 20 (1/1600) than at age 35 (1/370), but many younger women have children than older women. So most (75-80%) DS children are born to younger women. If a couple has a child with DS, there is usually an increased risk for a second affected child (Vogin, 2002).
All individuals with DS have an extra chromosome 21 material. There are three genetic bases for trisomy 21, the first and the most common is the disjunction where there is an extra chromosome 21 inside a cell. The second is the mosaic DS which is exhibited by trisomy 21 cells mixed with a second cell line which is normal and is of the 46XX or the 46XY chromosome. Individuals with this form of DS are a bit milder in their presentations, depending on the proportion of normal cells. The third is a translocation DS, about 3-5% of the total, where part or all of chromosome 21 is translocated to another chromosome, usually 14. Translocation DS does not vary with age. Children with translocation DS are indistinguishable from individuals with the usual form of DS (Cooley and Graham, 1991).
As far as we know, there is no relation of DS to drugs, diet, lifestyle and financial status, some suggest that a little more of the common families with Alzheimer's disease in one or more of the older family.
Non disjunction results from unequal chromosome division, usually in the egg of the mother cell production. This is the form of DS that increases the incidences of increased maternal age. But DS is so common; it cannot be rare even to young parents.
If a couple has a child with DS, the risk is higher for the next pregnancy. Obviously, this means that the risk is 99% that the next child will not have DS (Graves , 1990). If the risk is already 1/220 at birth, the risk at age 37, the risk is usually estimated as twice the risk for age. Risks for amniocentesis results are higher because half to three-quarters of DS fetuses die before birth of natural causes.
Down syndrome results when there are two chromosomes 21, one 14, and one t (14q21q) because this combination has 3 chromosomes 21, a trisomy 21 by a different genetic mechanism. Sometimes, a Robertsonian translocation is formed between a 21 and a chromosome other than a 14. There are Robertsonian translocations between 13 and 21; 15 and 21; and 21 and 22. The recurrence risks for DS for balanced carriers with these other translocations are taken to be the same as that for the t (14; 21).
In about one-fourth of translocation DS individuals, the translocation is inherited. When it runs in families, the carriers are usually unaware they have a translocation because there are no problems for the balanced translocation carrier. Only with the birth of a DS child or DS fetus by miscarriage, does the couple find out one parent is a translocation carrier.
A carrier parent can have a chromosomally normal child, or a child who is a balanced carrier like the parent, or a DS child. Curiously, the chance that such a couple will have another DS child depends on which parent is the carrier. When the mother is a balanced carrier of a t(14;21), there is about a 12% risk for another DS child to be born in each subsequent pregnancy. When the father is the carrier, the observed risk drops to about 3% for DS. The reason for this difference in risks is not at all clear.
Characteristics of a Child with DS
Congenital heart disease, usually in the form of endocardial cushion defects, affects 40% of babies and should be screened for by echocardiography soon after birth as it may well be difficult to detect. Septal defects and Fallot's tetralogy also occur. The discovery of severe congenital malformations often raises the issue of how interventive to be. It must be emphasized that exactly the same medical and surgical treatment should be instituted for a child with Down syndrome as for a child without a chromosomal disorder (Benke et.al, 1995).
Severe congenital heart disease remains a major killer of children with Down syndrome, despite advances in surgical treatments. In the absence of a congenital heart defect, however, the majority of children can expect to live into their sixth decade.
The commonest congenital abnormality of the gastrointestinal tract associated with Down syndrome is duodenal atresia, although pyloric stenosis, Hirschsprung's disease and tracheo-oesophageal fistulae have all been reported. Again, surgical intervention should be evaluated without reference to the chromosomal disorder. The total incidence of GIT malformations is approximately 12%.
In terms of feeding behavior, Hypotonia is a constant feature of neonates with Down syndrome. This floppiness can interfere with breastfeeding and an experienced lactation consultant may need to be involved to ensure that the process is successful. Feeding tends to take longer and there may be attachment problems due to a protuberant tongue. Some babies experience difficulty maintaining temperature and may need extra swaddling during feeding. Constipation is more common due to hypotonic gut musculature.
Other effects are on the congenital hypothyroidism; this condition is slightly more prevalent in babies with Down syndrome. It should be detected by the routine heelprick screen performed on all neonates. There is also congenital dislocation of the hips. Joint laxity and hypotonia can combine to increase the incidence of hip dislocation, although true congenital dislocation is quite rare. Extra care should be taken during the usual neonatal examination. Last effect is on vision. Three percent of newborns with Down syndrome will have dense congenital cataracts which should be removed early. Glaucoma is also more common
Why do we screen for Down's syndrome?
The medical profession has been criticized for allowing technical advances to outshine our ability to deal with the ethical issues which they raise. It is inspiring, therefore, to see paternalism being replaced by a conscious effort on the part of doctors to act as expert informers who allow parents to make their own decisions based on accurate facts. While the technical procedures require a high level of skill to be performed well, an even higher level of skill is required to handle the results appropriately.
Screening for DS is very important to the parents even before the woman gives birth to the child. Giving the diagnosis to a couple is either antenatally or in the immediate post partum period. Antenatal diagnosis means that DS will be detected before the birth of the child, when it is still in the womb of the mother.
Without screening, 1 in 700 babies would be born with Down's syndrome. Some hospitals in the UK
The disease should have an early stage that can be identified by a test. The early stage, in this case, is where the fetus is immature enough to be terminated if found to have the condition. There is no way of preventing the condition in the first place.
Several tests have been tried. There are four or five blood tests, and recently using ultrasound to measure the swelling at the back of the baby's neck (nuchal translucency) has improved the detection. Whatever test combination is used, a positive result means an invasive test such as amniocentesis or chorionic villus sampling (CVS) is recommended. Both of these involve sticking needles near the baby to remove the fluid around him, or a sample of the cells that make the placenta.
Down's syndrome should be screened because the consequences last for a lifetime. The cost of the existing programs is estimated to be less than the cost of the long term cost of caring for the affected child. The early tests are reasonably safe and accurate, but there is a big problem with the rates of miscarriage after amniocentesis and CV. These complications increase the earlier in the pregnancy that the test is done.
Giving the Antenatal Diagnosis
Although parents should have been prepared for the diagnosis of Down syndrome before the test took place, even the best pre-test counseling does little to offset the shock of an unexpected diagnosis. Initial shock and denial can be anticipated as part of a sudden shift in parental expectations. Most parents experience a need for concise, accurate and non-judgmental information on which to base their decision. Contact with the Down Syndrome Association might be helpful if the parents are agreeable (Platt and Carlson, 1992).
One of the great challenges for doctors when trisomy 21 is detected prenatally is to give a balanced and complete explanation of the options available to the parents so that they can come to an informed decision whether to continue with the pregnancy or not. This includes giving accurate information about Down syndrome and the range of expectations they could have for the child, while not trying to be impossibly predictive.
If termination of pregnancy is selected after adequate discussion, the full impact of that procedure must be explained. Careful follow up should be arranged to ensure that an appropriate grieving process for the loss of the pregnancy takes place. Insensitive statements such as "Forget this one and start again" are cruel and ignorant.
The detection of trisomy 21 prenatally does not always result in the termination of that pregnancy. During pre-test discussions with the parents, when information is given about the conditions being sought, it might become apparent that the couple would not choose to abort an affected pregnancy but just want to know of any defects so that they can be prepared for the baby's arrival. It is vital that all couples be adequately prepared for any screening tests so that they understand what the test is for, what its dangers are and what options are available should the test be positive for the condition being sought.
Types of Antenatal Screening Processes
There are several types of screening processes for the presence of DS in unborn children. Common types being used are quadruple method testing, Nuchal Translucency scanning plus prenatal diagnosis such as Chorionic Villus sampling and Amniocentesis.
The quadruple test is a method of screening involving the measurement of four substances in the maternal blood. These are alpha-fetoprotein (AFP), unconjugated oestriol (uE3), inhibin-A (inhibin) and free b-subunit of human chorionic gonadotrophin (free b-hCG). The test is performed between 14 and 22 weeks of pregnancy.
The maternal serum diagnosis is used in the detection of DS using the technology of an open neural tube. It is suitable for women of all ages and can detect the age of more risk by having an affected pregnancy. They will offer with diagnostic test after the screening.
Nuchal fold thickness is the most discriminatory ultrasound marker of Down syndrome at 15-22 weeks gestation on its own (Spencer et.al, 1999). However, it is not discriminatory enough to be used alone for screening. Studies investigating its role in combination with serum markers have not been completed to date. Nuchal translucency has also been found to be a useful marker at 10-14 weeks gestation, but lacks proper quantification of its performance alone and in combination with serum markers.
A consideration of amniocentesis must enter into any assessment of an older woman's risk of delivering a Down's syndrome child. This diagnostic procedure, which occurs in the midtrimester of pregnancy, involves the removal of between 15 and 30 ml of amniotic fluid from the intrauterine sac of fluid in which the fetus has been immersed since early gestation. A syringe attached to a long needle is inserted through the abdomen into the amniotic sac and withdraws the fluid. The concomitant use of ultrasound, a technique that permits visual access to the fetus, makes it possible to avoid accidental puncture of the placenta or inadvertently miss a second fetus (Barclay, 1997).
Amniocentesis of "high-risk" pregnancies at 16 weeks remains the commonest method of detecting those which are affected by trisomy 21. Such pregnancies are selected on the basis of maternal age being greater than 35 years or a previously affected pregnancy. The risk of having a second pregnancy with Down syndrome is 1% unless a translocation was the cause in which case the risk may be much higher. The procedure is not without its problems, however, which include an accidental miscarriage rate of 0.5 - 1% and the potential need to perform a mid-trimester abortion if that is the option selected by the parents (The Down Syndrome Association).
Another type of screening is the Chorionic Villus Sampling. This procedure involves the transvaginal biopsy of the developing placenta at 10 to 12 weeks gestation (Spencer et.al, 1999). It has the advantage of earlier detection of chromosomal abnormalities than is possible with amniocentesis but it is associated with a higher rate of post-procedure miscarriage (2-5% depending on the operator). Concerns have been raised over limb and jaw defects in fetuses which have undergone the procedure but hard data is lacking.
Giving the diagnosis of Down's syndrome to a couple antenatally, requires all of the doctor's communication and counseling skills. It is the general practitioner to whom most parents would prefer to turn for this information. If an abnormality is detected, the mother has a number of options to consider: elective abortion, continuation of the pregnancy while making special preparations for the birth of the child, and others as agreed upon with the doctor's advice.
Cost Effectiveness and Safety of Antenatal Screening
In classic cost-benefit analyses, the costs of the screening tests are weighed against the lifetime cost of caring for people with Down syndrome. Such comparisons however lack consideration of individual choices and the impossibility of placing a monetary value on human life (Fletcher et.al, 1995). Screening for Down Syndrome aims to allow parents to prepare for the birth of their child, emotionally and mentally. In countries and societies where abortion is available, screening is utilized by some as a means of terminating the pregnancy before its completion. With this in mind, screening has to be approached with great sensitivity.
Pre-screening counseling and the exploration of expectations and motives have to be undertaken with the parents-to-be. Physicians have to carefully guide parents through the implications of test results, as the predictive values are not absolute. Additionally, the choice to undergo further invasive antenatal diagnostic tests carries inherent risks towards the fetus.
In this respect, more detailed screening reduces the number of women undergoing an invasive diagnostic procedure that may result in fetal loss. The number of unaffected fetal losses per Down syndrome birth avoided declines by 24% from 0.59 (double test) to 0.45 (quadruple test).
The fetal loss rate due to amniocentesis is 0.9% with a mid range estimate of 0.6-1.2%. Transcervical CVS seems to result in more fetal losses than trimester amniocentesis and possibly first trimester transabdominal CVS, but the issue is not totally resolved. Transabdominal CVS and mid trimester amniocentesis each have a similar excess risk of fetal loss. This is supported by direct evidence (Fletcher et.al, 1995).
Cost of screening is not another issue of the parents concerned with DS. Cost of amniocentesis is £150; this was derived from £120 for the cost of amniocentesis and karyotyping, £20 for the cost if the obstetrician, midwife and ultrasonographer, and £10 for consumables and depreciation of equipment. The cost of CVS was estimated to be £250. Termination of pregnancy after diagnosis of fetal loss is also common. The uptake of termination was taken as 90%. The cost of termination of pregnancy was £475 (Selikowitz, 1990).
There are thus 2 distinct questions in cost effectiveness calculations for screening. Firstly, which method of screening is the least expensive method of achieving a given detection rate. This should be determined for average cost per affected birth avoided or case diagnosed. Secondly, what is the extra cost of increasing the detection rate by a specified amount when a particular method of screening is being used. This should be determined from the marginal costs.
Psychosocial Aspect of DS Antenatal Screening
Screening necessarily causes anxiety because it identifies individuals with a high risk of serious medical disorder (Wald et.al, 1998). It effective creates patients from the general population of pregnant women by identifying some as being at increased risk. A positive screening result makes the awareness of the risk real and personal at a particularly emotional time because of the strong emotions associated with pregnancy. Screening makes uncertainty explicit, and this itself can be distressing.
It is the duty of the screening service to provide appropriate information and personal support so that the anxiety generated by screening is constructive and necessary- helping women to make decisions that they feel are right for them. Screening should not be confined to simply performing tests and reporting the results. Screening is often seen as a means of reassurance, rather than a means of identifying abnormalities, and is apt to raise expectations than a negative screening result rules out the possibility of an affected pregnancy. This must be guarded against.
Women need appropriate knowledge of the screening test, together with the limitations of the test, so that they can decide whether they wish to be screened (Wald et.al, 1997). They need to consider their possible action if a test result suggests that antenatal diagnosis is indicated and if DS is subsequently diagnosed. It is important for them to recognize that a screen positive result does not necessarily mean that their pregnancy is affected and that a screen negative result does not provide reassurance that they are no longer at risk.
Much that is often considered as the psychosocial aspect of screening concerns the self-evident need to provide a well-informed, compassionate service that respects the wishes of individuals. Nevertheless, it is often in this area that screening fails and causes casualties that could, with appropriate care, be avoided. Various studies have examined the activities of the health professionals who help to provide the service.
Midwifery- The Social Context of Childbirth
According to Julia Drown MP, chair of the maternity services subcommittee that produced the report, some providers are leading by example – and their work illustrates that barriers for these groups can be overcome. Generally, however, maternity services for different groups can only be described as 'patchy', with good practice rarely shared across the health service. 'This is deeply disappointing because it means that families across the country are not getting access to the services that they need,' she says.
Helen Burchett, public health policy officer at the Maternity Alliance, agrees that certain groups of women are not receiving adequate care (Snijder et.al, 1998). She believes the problem partly stems from the fact that the health service doesn't collect data to establish how many disadvantaged women are living in any one locality. As she points out: 'If you don't know how many people are living locally, then you can't allocate resources and design a service that is suitable for them.'
It is not just about ensuring access to services, however. Providers need to think about what they offer once the woman is through the door. 'There is a lack of awareness and understanding of what these women's needs are. In our research, we have found that prejudice and discrimination does exist,' says Burchett.
The parliamentary subcommittee agrees. Drown says women's experiences of maternity care varied, depending on the attitudes of individual staff: 'Prejudice in relation to class, race or disability profoundly affected women's experiences of pregnancy, birth and motherhood,' she adds. Nevertheless, the report did find a number of examples of good practice. These include work being carried out by midwifery group practices set up by the Southampton University Hospitals Trust and the activities of the One to One scheme, funded by Hammersmith, Ealing and Hounslow primary care trusts.
Maternity Antenatal Services
Development of the maternity services for the betterment of the service to the pregnant women should be made. Midwives relationship to the women should be of good terms so that it can be a well harmonized rapport (Mansfield
National Perinatal Epidemiology Unit and Maternity Alliance (NPEU-UK) found surprisingly little recent evidence about patterns of attendance at antenatal care for different social groups. The exception to this was a study done in the mid-1990s that suggested that on average women from South Asian backgrounds started care later and had fewer visits than White women. There were no recent studies that described antenatal care for women from different social class categories. We also found evidence that women of South Asian origin might be up to 70% less likely to receive prenatal testing for haemoglobin disorders and Down's syndrome. A small number of the studies distinguished between the offer of screening and its uptake and these suggested that South Asian women might also be less likely to be offered testing. National and local responses are needed to address these gaps in provision.
The NPEU Memorandum started from the position that poorer people in UK
The findings from the Confidential Enquiries in Maternal Deaths make it clear that some of the women who die are not receiving appropriate antenatal care, but the response to these needs to be based on better evidence about who misses out on care and at what point (Royal College of Obstetrician and Gynecologist). Any study of inequalities in antenatal care and screening needs to look at women's pathways to care: do some women delay their approach to a midwife or GP at the beginning of pregnancy? Are there referral problems? Are some women unable to get to the hospital for specialist care because of the practical difficulties or cost of transport? Do all women get accessible information about screening and opportunities to ask questions? Are there specific groups with particular problems in accessing care? At present we do not have answers to any of these questions. Once we know more about the gaps, and about women's experiences of accessing antenatal services, we can test out different solutions.
Maternity Services Improvement Programs
In 2000, the midwifery groups were set up in the Weston Brooke, Shore, Millbrook and Redbridge, Thornhill and central Southampton . All neighborhoods ranking high on the deprivation indices, with ethnically diverse communities include the asylum seekers, homeless women and prostitutes. Three of the groups work in partnership to Sure Start (the project was partly funded).
Each midwife has a caseload of 36 women every year. Unlike traditional, hospital based services, they work in the community. They are also responsible for their clients throughout pregnancy, birth and the post-labor period – so they have a chance to bond with the mother and are able to provide continuity of care.
In addition, they visit clients at home, so they can identify any broader health needs; they are encouraged to work with a range of partners, from housing and education to the local furniture recycling shop, to help meet those needs. Karen Baker, associate director of midwifery and nursing at Southampton University Hospitals Trust, points out that this kind of holistic approach is needed if the health of these mothers and their babies is to improve.
Their efforts appear to be paying off. No formal evaluation has been undertaken, but data collected last year indicates there were three times as many emergency caesareans in a similarly deprived area, where traditional services were being used, than in Weston Shore
In West London, the Queen Charlotte's and Chelsea Hospital Southampton , its 24 midwives use the caseload approach – supporting 40 women each annually. An analysis of the scheme, by Thames Valley University
Initially, the service was available to all local women. But following a Royal College of Midwives recommendation that midwifery services should strive to ensure continuity of care for women from disadvantaged backgrounds, the decision was taken to focus on vulnerable groups. (Vision 2000 Royal College
The National Institute for Clinical Excellence (NICE) and the National Collaborating Centre for Women's and Children's Health published guidelines on the care of healthy pregnant women. The recommendations cover a range of issues including: the provision of evidence-based information to help the women make informed decisions; the number of antenatal appointments they should have – and what should happen at each one; the use of ultrasound scanning; and the provision of screening for a range of conditions, including gestational diabetes, HIV and Down's syndrome.
Disadvantaged women faced a number of barriers when accessing maternity services including: prejudice in relation to class, race or disability; lack of advocacy and interpreting services; lack of community care, particularly for homeless women and dispersed refuge seekers; little support for mothers with disabilities; lack of consultation; an insufficient number of mother and baby units for women suffering from severe mental health problems; the dispersal system exacerbates the barrier to maternity services faced by women seeking refuge.
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