Are there any new advances in pregnancy testing?

Yes. New tests are being developed which con-centrate on detecting chemical changes in easily accessible body fluids like saliva and urine.

Scientists in this held are trying to move away from any tests involving the use of blood samples (simply because they are more difficult to obtain), and attempts are also being made to develop tests that avoid the use of radioactive chemicals. And further, there is a move towards producing anti-HCG in cultures rather than extracting them from the blood of animals.

It has been found that several different protein substances, not normally present in a woman’s body, are produced when she is pregnant. Work is being done to develop tests that detect the presence of these substances. Tests are also being developed to detect a particular enzyme known to be present in the saliva of pregnant women.

A further recent discovery has been that pregnancy alters the body’s production of white blood cells. It could be that the detection of this alteration in lymphocyte function will form the basis for a future pregnancy test, but this line of research is in its early stages at present.

In addition, the sensitivity of ultrasound detection is continually being improved. It is already possible to ‘see’ ovulation and, as mentioned earlier on, the developing embryo can be seen in the womb by the sixth week of pregnancy. A leading specialist in the field claims that soon, the stages between ovulation and the six-week-old embryo may also be detected visually. In fact it is thought likely that the ultrasound scan will prob-ably be the main form of pregnancy testing in the not too distant future.

H undreds of thousands of women each year give birth to healthy babies after a trouble-free pregnancy. Nature has provided an ideal environment in the womb.

Unfortunately, complications do occur, but with an ever-increasing battery of tests at their disposal, doctors can identify problems early and, if necessary, intervene to help both mother and baby. But for this checking process to be effective, it must be regular and must start early in pregnancy. Each appointment for an antenatal check-up may be crucial to the health of the developing baby.

What are the normal screening tests done during pregnancy? A programme of physical examinations and medical tests help doctors to identify any poten-tial problems early in pregnancy. Some of the procedures are ‘one-offs’, others become a regular part of each ante-natal visit, so that doctors can monitor the progress of both mother and baby.

This ‘screening’ starts at the first ante-natal visit, which should take place within 12 weeks of conception, and continues until the birth of the baby! Apart from regular physical check-ups -internal and abdominal examinations and weighing – certain medical tests also become part of the routine. Urine samples and blood pressure readings are taken at even- visit while cervical smears or blood tests may only be needed once or twice throughout the pregnancy. Ultrasound screening is also a normal check in some centres.

After the first ante-natal visit, mothers are usually asked to come back even- four weeks. At the 28th week, the gap between visits closes to two weeks, and then to one at the 36th week up until the baby is born. Sometimes the findings of these routine check-ups will indicate that further tests may be necessary.

Why do doctors sometimes recommend special screening tests? Nd the . An ‘ illness, perhaps running in the family, may affect the unborn child.

Women suffering from diabetes, high blood pressure, kidney or heart disease, and even alcoholism or drug addiction are all considered.

At the first ante-natal visit, do expectant mother’s medical progress of any earlier preg to be “high risk”. They will automatically be given tests to check on their baby’s size and growth. Indeed, whenever a doctor suspects that a baby is not thriving properly he will recommend that these tests be given. Small babies with a low weight are more likely to be born prematurely and to risk physical or mental handicap. Doctor’s will also run tests if they suspect that a mother is carrying more than one baby, or if she has a previous history of miscarriage or stillbirth. Older women and very young women particularly those who are single or living in very deprived circumstances, will also be candidates, since they are more likely to encounter complications.

Older women run a greater risk of having a mongol baby too (Down’s syndrome) – one of the better known of the ‘genetic’ problems. A complication of this kind, which results in mal-formation, is one of the things parents fear most and a major reason for running special tests. There are a number of disorders which can cause abnormality in babies, some of which do run in families. Fortunately, it’s possible to detect them while the child is in the womb, and if necessary to terminate the pregnancy.

Hormone levels in the mother’s blood and urine can sometimes give doctors guidance on die progress of ‘high risk” babies, and some abnormalities may be detected during routine ante-natal tests. For instance, signs of spina bifida, which can cause major malformations, can be seen in blood tests. But pre-birth screening has been revolutionized over the past 10 years by two new techniques – ultrasonic screening and amniocentesis (the fluid test). Women with a high risk factor or a family history of inherited disease can now be screened by these methods as a matter of course.

Ultrasound gives doctors a ‘window5 on the womb, providing information that often cannot be gathered in any other way. It is now commonly used in the routine examination of pregnant women, even when there is no suspicion of any abnormality, just to confirm dates. The technique uses a series of high frequency sound waves – inaudible to the human ear -which ‘bounce’ back from the foetal tissue according to its density and depth. These sound waves build up to form an impression of the baby – his first ‘photograph’ in fact. Unlike X-rays hich are only used as a last resort, it also has the advantage of being harmless.

The mother lies on a couch and her stomach is given.a smearing of olive oil to give the scanner ‘head’ a good ‘contact’. The scanner moves backwards and forwards and up and down and the mother can often see the baby’s outline appearing on the ‘screen’ – an exciting moment.

Ultrasound screening can be valuable in pre-venting handicaps in babies. Premature births, for example, can be avoided, since screening allows doctors to assess the exact age of the foetus and so time delivery. Diabetic babies, can also be closely watched, and signs of bleeding from behind the placenta can warn doctors that the baby is in danger of oxygen starvation – one of the major causes of either handicap or death.

Of the most important functions is in aiding amniocentesis (the fluid test) in detecting malformation. In skilled hands, an ultrasonic scanner can actually reveal the damage caused by ‘open’ spina bifida.

Regular checks will follow the baby’s progress. A sudden fall in the growth rate could mean that the mother needs to rest, or that the placenta is failing to deliver enough oxygen and that the baby must be delivered. A misplaced placenta can confirm the need for a Caesarian delivery.

The baby’s weight can also be assessed with the aid of the ultrasonic scanner, and this can ensure that the best facilities and care are available to very small babies. Similarly, twin and multiple births can be diagnosed as early as seven weeks, so that both parents and doctors can be forewarned and preparations made. A baby’s heartbeat, too, can be detected long before any stethoscope would be able to pick it up.

Basically, this involves taking a sample of the amniotic fluid which surrounds the baby.

The sample is drawn off by inserting a fine, hollow needle through the mother’s abdomen into the womb. This is neither as frightening nor as strange as it sounds. The woman lies comfortably on her back, while the doctor checks the position of the baby so that he knows precisely where the needle should go. A small amount of local anaesthetic is rubbed over the skin, so that as the needle goes in there is no pain, only a slighdy strange feeling.

The fluid does not ‘leak’ out of the womb- the tissue in the wall simply closes over the ‘puncture’ as the needle is withdrawn.

The fluid contains cells shed from the baby’s skin, and from these doctors can detect signs of any inherited defects. It also contains traces of a substance called alphafetoprotein (AFP). High levels indicate the presence of ‘neurological’ disorders such as spina bifida.

It is crucial that the tests are carried out at the correct time- usually between the 16th to 18th week of pregnane)’ – when results should be much clearer. But the one disadvantage of this timing is that, should an abortion follow, it will take place later in pregnancy than is normal.

Many doctors would like to see the screening of blood, followed by a fluid test if necessary, introduced all over the country to detect spina bifida. Three or four out of ever)’ 1000 preg-nancies result in ‘neural tube’ disorders of this kind, and screening is estimated to detect three in even’ four affected infants. Already, a large number of doctors recommend that all pregnant women aged about 40 or over should be tested for mongolism, if they wish, since the risks rise steeply at this time. No mother is obliged to have these tests, and if your doctor recommends that you have them you can always discuss it with him if you have any doubts.

Yes. When the fluid is tested for inherited disorders, it can also reveal the sex of the child, but the test is not available to those who simply want to know whether their baby is a boy or a girl.

This is not because it would take the mystery out of pregnancy – and many parents enjoy this | guessing game- but because it could be open to | abuse. Already some parents have begun to demand abortion as of right if the child is of the ‘wrong’ sex.

The most up-to-date equipment, which is not vet commonly available is a ‘real time’ scanner which can also pick up the baby’s movements as they take place. Such movements can be detected in a foetus that is only eight weeks old.

Blood can be seen coursing through the veins and the heart beating. In late pregnancy the scanner can show the baby’breathing’ or making some form of respirator)’ movement. This has enormous benefits in checking the baby’s well being, and some researchers believe that in the future this scanner may make it possible to operate on the baby in the womb; in the case of heart defects for example.

The newest techniques also permit the exact diagnosis of some disorders for which a blood sample from the foetus is needed. A letoscope can extract a sample from the placenta and this can be tested for haemophilia or muscular dystrophy. The fetoscope has a tiny built-in light and may even help to explore the baby for defects such as a cleft palate.

No. Babies do not follow such a strict timetable that they all require exactly 40 weeks in the womb. Some may need a little more, some a little less. Although ultrasound is the most reliable guide to estimating the age of the foetus we have, it is not infallible, and doctors and midwives are warned not to rely on it too heavily.

As with all medical procedures, risk must be balanced against the advantages. As far as we know the high frequency sound waves of the ultrasound scan do not damage the foetus, and there has been considerable research to support this belief.

Amniocentesis carries a slight risk- perhaps a two per cent chance of miscarriage. But in the centres with the best experienced and most highly skilled operators, the risk is even less. Nevertheless, because of the slight chance- of harming the child, doctors do not always encourage the test. If a woman over 40 is carrying a much-wanted first baby, aftcryears of infcrtilitv, the doctors may advise against amniocentesis, though mongolism may be a risk. Younger women, who have much lower chances of having mongol children are not normally tested either. And in any case, you are not obliged to have them.