Screening Tests During Pregnancy

Having a normal pregnancy and getting a healthy baby are the greatest happiness for each expectant mother and her family. No problems are experienced in most pregnancies. However, regular monitoring starting from the period, in which pregnancy is desired, and throughout pregnancy helps expectant mothers have a baby in a safer and healthier manner.

Throughout pregnancy follow-up, former and current diseases of the expectant mother, results of previous pregnancies and the complaints about this pregnancy are investigated. Examinations relating to pregnancy are carried out, blood pressure is measured, weight follow-up is ensured, blood type is identified and blood count and urine tests are performed. The purpose in doing all these is to identify the diseases that might appear throughout pregnancy and make sure that the fetus is developing in a healthy manner, realize possible risks beforehand and take precautions or administer the best treatment for those that have happened without delay.

Apart from the tests performed in a pregnancy that makes a normal progress, there are also advanced tests that are performed in special cases, as well. The procedure carrid out to identify those among a group of people that have a higher risk of coming down with a specific illness is called a Scan. A scanning test is and should be a test that is usually carried out easily and that can be performed on everybody. The aim of a scan is to help reveal a disease rather then diagnosing it. A more advanced method is usually needed for the final diagnosis. Antenatal Scans are scans carried out to identify a health problem in the pregnant woman or the fetus.

Tests relating to the health of the mother:

• Scanning for diabetes ( Glucose screening test)
• Scanning for Blood group and RH incompatibility
• Scanning for Infectious diseases
• Ultrasonography examinations

Test relating to the health of the fetus:

• A scan of fetal anomalies and chromosomal anomalies
• Double test
• Triple test
• Measurement of the Alfa Fetoprotein (AFP) in the mother’s blood
• Nucal translucency scan
• Interventional procedures in prenatal screening
• Amniocentesis (taking a sample of amniotic fluid from the mother’s womb)
• Cordocentesis (drawign blood from the umbilical cord of the baby)
• Chorionic Villus Biopsy (KVB)

Scanning for Diabetes  (Glucose screening test)

Pregnancy causes diabetes in some pregnant women or reveals diabetes that was previously not known. Diabetes due to pregnancy is called gestational diabetes. Gestational diabetes might lead to delivery of overweight babies, dystocia, health problems in the pregnant women or the baby and death in the womb. Blood glucose must be investigated in all pregnant women once in the first three months. Apart from that, a Glucose Screening Test is carried out between the 24th and 28th weeks of pregnancy in order to identify pregnant women with gestational diabetes.

This test is carried out at any time of day. Glucose level in blood is measured 1 hour after a sugary drink (containing 50 grams of glucose) given from the laboratory. If the test result is low, that means gestational diabetes is not present. However, if the test result turns out to be high (the admitted limit is 140 mg/dl), the need to perform another Test (Oral Glucose Tolerance Test) which will a provide more correct result for the final diagnosis arises. In this second test, glucose level in the blood is measured by making the patient drink 1 glass of liquid again and drawing her blood every hour for 2-3 hours. If the gestational diabetes diagnosis is confirmed, diets of these pregnant women are designed accordingly, insulin therapy is started if necessary and the pregnant women are followed more closely.

Scanning for Blood group and RH incompatibility

Blood group and RH status of each pregnant women must certainly be known. The RH structure in human beings comes in two types Rh (+=plus=positive) or (-=minus=negative). There are no problems if the blood group of the pregnant woman is Rh (+), but if her blood group is Rh (-) then the blood group of her husband is checked. If  her husband’s blood group is Rh (-), there are no problems again but if her husband’s blood goup is Rh (+), then there is Blood Incompatibility in that pregnant woman.

A pregnant woman with blood incompatibility is monitored with some special additional tests. This test is called the Indirect Coombs Test and it is checked from the mother’s blood. If no problems arise throughout pregnancy, that is, if the blood incompatibility does not transform into a disease, an injection is given to the mother after birth if the blood group of the baby is Rh (+) but nothing needs to be done if its blood group is (-).

The injection to prevent blood incompatibility (Anti Rh D imminoglobulin) is given after deliver yor during pregnancy for protection purposes in some special cases. It will be prescribed by your doctor. Your doctor might sometimes ask you to have the injection in the 28th week for protection purposes. However, the injection must be repeated after birth according to the blood group of the baby even if the was given in this way.

Scanning for Infectious Diseases

Whereas having some infectious diseases for the first time during pregnancy does not have any effects on the fetus, they might lead to some diseases.

According to the opinion of the Perinatology Association, a pregnant woman must be checked for rubella, Hepatitis B infection and her urinary culture must be investigated once. A scan for syhphills must be carried out on the risk group only. The association believes that there is not sufficient evidence that supports scanning pregnant women for toxoplasma and CMV, HIV (AIDS).

In the light of this information, your doctor will make you have the tests he considers to be necessary in your special condition, please follow the advice of your doctor.

Ultrasonographic Examinations

Opportunities offered by developing technology leads to great progress in all fields of medicine. Ultrasonography examination has gained importance in pregnancy care today. It has a very important place in prenatal screening. However, pregnancy care is not given through ultrasonography only, examination is the most important part in pregnancy care. Ultrasonography cannot replace examination and if the pregnant woman has ultrasonography examination only and does not care about or delays the other follow-ups that need to be carried out by the midwife and the doctor, this might lead to reverseless and vital diseases and undesired results.

There are no findings showing any detrimental effects of ultrasonography devices that are allowed to be used on pregnant women on a fetus in its mother’s womb and they can be used confidently during pregnancy. However, as is the case in all the other medical methods, they should only be used when necessary, with the appropriate device and by expert staff.

Number and heart beats of the fetuses in the mother’s womb and whether these fetuses are alive or not can be identified, age of pregnancy can be appointed, growth of the fetus and its position in the womb can be monitored, amount of the amniotic fluid, development of internal organs and other structural developmental defects and the placenta feeding the baby can be evaluated. Ultrasonography is also used to search various diseases in the baby and related clues and findings. Ultrasound is usually performed through the skin of mother’s abdomen. Vaginal ultrasound, on the other hand, is usually preferred during the early period of pregnancy. A transvaginal ultrasound is not a hurting procedure and does not carry risks like infection or miscarriage. Transvaginal ultrasonography can also be used to measure the length of the cervix to identify the risk of preterm birth in the advancing weeks of the pregnancy.

Ultrasonographic Examination in Pregnancy Care

• Detection of the normal growth of the fetus
• Detection of the problems with the fetus
• Advanced investigations can be classified under three main headings

Ultrasonography is not a must in every pregnancy examination: a woman is required to be examined through ultrasonography at least three times throughout her pregnancy, namely, 11th to the 13th, 20th to 21st and 30th to 32nd weeks.  If your doctor feels it to be necessary, he/she might ask you for a stricter care, as well or guide you to another (second-line) instituition for advanced investigation.  Each pregnant woman mjst be considered by a gynecologist working in the field of perinatology in more experienced centres with respect to the defects (scanning for disability, anomaly) in the fetus at least once during about the 20th to 22nd week of pregnancy (second order ultrasonography).

Ultrasonography provides us with very valuable information about the health of the fetus. However, all diseases of the developing fetus cannot be diagnosed with ultrasonography. A majority of the fetus’s great defects can be recognized through ultrasonogprahy but it is less successful in evaluating the development of the fetus and recognizing insignificant defects. Besides, some diseases might appear in the advancing weeks of pregnancy and might not have been recognized in previous ultrasonography scans. Probability of the ultrasound performed tı detect the defects in the fetus changes between 20 to 80% depending on the age of pregnancy, in which the examination is being carried out, experience of the performer and the technical specifications of the ultrasound device.  In a comprehensive study carried out in Europe it was proven that only 60% all anomalies can be detected with ultrasonography. Therefore, there is warning in ultrasonography reports to inform you that not all kinds of defects can be recognized via ultrasonography.

Special Ultrasonographic Examinations

Second-line ultrasonography: Is the name given to the detailed ultrasonographic examination of the fetus to detect birth defects. It is suitable to perform the ultrasonography that is aimed at scanning anomalies between the 20th and 22nd weeks of pregnancy. It is not possible to detect all birth defects in second-line ultrasonography, either.

Doppler Ultrasonography: Detects changes in the blood flow rates in the veins of the mother or the fetus. Changes in these values are useful for informing us on some diseases relating to the mother or the fetus and evaluating the well-being of the fetus. Development of high blood pressure in the mother (preeclampsia which is colloquially known as toxemia of pregnancy) and growth retardation resulting from placental insufficiency in the baby are the most significant areas of its usage and guide the treatment plan.

Fetal Echocardiography: Examination of the fetus’s heart via doppler ultrasonography. Heart diseases of the fetus are searched for. It is best evaluated in the 22nd to 24th weeks of pregnancy. Helps fetuses which might have difficulties after birth due to heart diseases to be sent to higher centres for birth. Fetal echocardiography is a technique that requires special equipment and experience. It cannot be performed on every pregnant woman. It is aimed at mothers or fetuses that carry certain risks. Structural defect anomalies in the fetus, congenital heart defects in the family, diabetes in the mother or some infectious diseases are examples to these risks.

Three Dimensional Ultrasonography: Is the examination, with which three dimensional images (like photographs) of fetuses can be obtained thanks to technological developments. If the image is obtained simultaneously and instantly this is called four dimensional ultrasonography. Ultrasound devices widely used today being sufficient, a three dimensional examination is needed very rarely.

Scanning for fetal anomalies and chromosomal anomalies

Predictions on the health of the fetus can be made based on some tests performed in the mother’s womb. It has been understood that, when compared to the blood values of mothers of healthy fetuses,  the blood values in the blood of mothers of some diseased or disabled fetuses are different. This difference does not ensure a final diagnosis but it requires putting risky fetuses to more advanced examinations. Performing advanced tests on all pregnant women is, eventually, both unnecessary and impossible. Furthermore, some of these advanced tests carry risks for the mother and the fetus. Therefore, advanced techniques (interventional procedures such as chorionic villus biopsy and amniocenteses) are recommended to the expectant mother if the results of the screening tests identify a high risk. Likewise, the fact that the results of the screening test point to low riskrisk is low (for example, a probability of 1/1000) does not guarantee that the fetus is certainly not ill. It only shows that advanced tests, which are riskier, are not necessary as the risk is too low.

The approach today is to explain Screening Tests to all pregnant women and perform them on all applicants.

Down Syndrome

Chromosomes are the smallest structural units in which the genetic information determining all the functions and characteristics of the living things are recorded. Number of chromosomes in humans is 46. There is an extra 21st chromosome in individuals with Down Syndrome, which is a genetic disease, that is, individuals with Down Syndrome have 47 chromosomes. Down Syndrome is the only chromosomal disorder that agrees with life and the most frequently observed chromosomal disorder among live births. Increased age in mothers plays a significant role in the appearance of this syndrome. Whereas prevalance of Down Syndrome among live births is 1/1500 when the mother is in her twenties, such prevalance is 1/30 when the mother is 45. Children with Down Syndrome have mental retardation, heart diseases and serious health problems in differing degrees. Various tests are used in scanning for Down Syndrome (Double test, triple test, nuchal translucency scan etc).

Double Test

This is a screening test that identifies risks with respect to specific chromosomal disorders in the fetus. The actual intended use of this test is to identify Down Syndrome. It provides results relating to Down Syndrome (Mongolism ) and Trisomy 18 Syndrome. Results indicating high risks do not mean that the fetus has this syndrome but require the performance of advanced examinations.

This is an investigation carried out between the 11th and 13th weeks of pregnancy. Two hormones (PAPP-A and free hCG) from the mother’s blood are measured and a risk measurement is performed. Its advantage over the triple test is that it is performed earlier. Advanced tests, if required according to the results, are performed earlier. It helps identify a fetus with Down Syndrome in the earlier weeks of pregnancy.

70% of fetuses with Down Syndrome can be identified if just those which are under risk according to the result of the double test go through advanced examination. Furthermore, if results of the double test are combined with the results of the nuchal translucency scan (see nuchal translucency) which is given via ultrasonography, this percentage rises up to 85-90%. This is called the First Trimester test or Double Test. The first trimester test (accompanied by the nuchal translucency measurement) is more successful in detecting fetuses with Down Syndrome than the triples test performed in the second trimester. The most important drawback of the first trimester test is that it cannot detect neural tube defects.

Triple Test

This is a screening test that identifies risks with respect to the developmental defects of the neural system (neural tube defects) in the fetus and chromosomal disorders (Down Syndrome (Mongolism) and Trisomy 18 Syndrome). Results implying a high risk does not mean the fetus is ill, it just requires performance of advanced investigations.

It is a blood test performed between the 15th and 20th weeks of pregnancy. It yields the best results between the 16th and 18th weeks. Three hormones (AFP, hCG, Estriol) are measured in the blood drawn from the mother and a risk measurement is made.

Gestational week, age, body weight, race of the mother and whether she has diabetes or is a smoker must be known while performing the test. Giving exact information on the mother’s age of pregnancy is very important. A risk assessment is performed for the diseases above by entering all this information and the values of the three hormones checked from the mother’s blood into a computer program. The results are identified separately both in terms of age only and as risk assessed with these hormones. If risk has increased (for example, if the probability of giving birth to a baby with Down Syndrome has risen up to 1/200), then whether the fetus actually has Down Syndrome. Therefore, advanced techniques are  recommended (see Amniocenteses).

Triple test is a test recommended to each expected mother to have between the 16th and 18th weeks. You should not forget that its a screening test. Therefore, other problems must be searched for via a detailed ultrasonographic examination must accompany this test between the 20th and 22nd gestational weeks.

The triple test might help detect the risk of some congenital abnormalities. These abnormalities are Down Syndrome, neural tube defects and some rare hereditary-genetic factors. If an advanced investigation is carried out based on the result of the triple test, 60-70% of babies with Down Syndrome will be identified. Advanced versions of this test have been recently developed to be able to detect a higher number of Down Syndrome cases (known as the Quad Test).

The fact that the triple test is performed in a relatively later period of pregnancy, the test results are obtained late and that termination of the pregnancy coincides with a late period such as between the 20th and 22nd weeks in the case that the results show a diseased baby constitutes an important drawback.

Prescribing both the double and triple tests to the same pregnant woman are considered to be unnecessary today. The double test (the first trimester test), which is investigated together with the nuchal translucency measurement, is preferred as it is more successful, more reliable and performed in an earlier period. On the other hand, a Triple Test must be performed on a pregnant woman who has missed the Double Test.

Measurement of Alpha Fetoprotein in the mother’s blood (AFP)

If there are some neural system development disorders (neural tube defects) or defects relating to the abdominal wall, it will be found out that a substance checked in the mother’s blood (alpha fetoprotein=AFP) has increased. Spina bifida can be cited as an example of neural tube defects. Measurement of alpha fetoprotein is a screening test used to come up with these defects at a time when ultrasonography devices did not exist. It is not prescribed for this purpose by itself today. These neural tube defects are recognized more easily thanks to the improvement of the image quality of ultrasonographic devices now. Prescription thereof by itself has decreased also because it is a hormone that is checked within the Triple Test. Only AFP can be checked in the 16th-18th gestational weeks if a double test has been performed. A detailed advanced level ultrasonography is required if AFP turns out to be high. However, searching for AFP does not contribute much as a detailed ultrasound will already be recommended around these weeks even if AFP does not turn out to be high.

Nuchal Translucency Measurement

Measurement of nuchal translucency of the fetus via ultrasonography between the 11th and 13th weeks of pregnancy. Probability of some chromosomal disorders (like Down Syndrome (A mongol fetus)) and organ defects in the fetus increases if nuchal translucency is found out to be higher than specific values. 75% of ploidy defects are detected in advanced investigations carried out based on the results of this test.

The aim in pregnancy care is to detect diseased fetuses in the earliest period possible. If a problem is detected in the fetus, an intervention can be made in an earlier period and simpler and safer methods can be employed to terminate pregnancy.

The approach adopted today is to explain this investigation to all pregnant women and carry out on those who desire.

Other Down Syndrome screening tests cannot be used in multiple pregnancies. Therefore, only nuchal translucency is measured for each baby separately and the risk assessed is taken into consideration.

When the nuchal translucency test and turbinate bone control in the fetus is evaluated together with the result of the double test (beta-HCG and PAPP-A measurement) (the first trimester test) with a special computer program, 85-90% of fetuses with Down Syndrome can be estimated. The first trimester test is the most sensitive among screening test used to identify Down Syndrome risk.

Nuchal translucency of the fetus normally increases as the gestational week progresses. Nuchal translucency between the 11th and 13th gestational weeks are measured with sensitive ultrasound devices today. The value obtained is compared with the values of that gestational week with the help of a special computer program. The risk of existence of Down Syndrome in the fetus is finally found out.

The probability of a diseased child increases as nuchal translucency goes beyond the standards. The reason might be chromosomal disorders (trisomy 21=down syndrome, trisomy 18, Turner syndrome), heart diseases, lung diseases, diseases related to the skeletal system, infections and other diseases in the fetus.

Apart from nuchal translucency, some fundamental structural developmental disorders (such as brain development, arm and leg development etc) can be detected earlier as the examination is carried otu with ultrasound.

Consequently, such interventional methods as amniocenteses or chorionic villus biopsy and advanced ultrasound examinations are recommended when high risk is detected in expectant mothers put through this examination.

Interventional procedures in prenatal screening

Medical procedures carried out by entering the body through the skin or natural entrances opening to the outside are called interventional procedures in medicine. These procedures include some risks like wounding. Interventional procedures are not recommended for every pregnant woman due to certain risks. You will be recommended to have interventional procedures if considered to be necessary by the doctor based on the risk identified in other screening tests. The family will decide together with the doctor but the final decision belongs to the family.  If the family accepts the procedure recommended, it will have accepted possible risks as a result of the procedure (complications=unavoidable disappointing results, as well. To this end, the pregnant woman and her husband must read and sign the informed consent. Whereas there is the risk of losing the baby due to the procedure in interventional procedures, there is the risk of giving birth to a diseased child for a family not accepting the interventional procedure.

As there are no other methods that will ensure a final diagnosis without including risks for the mother and the baby, these interventional procedures are required to detect some diseases in the fetus. New medical developments in the future will decrease the need for these methods.

Amniocenteses (Taking a sample of amniotic fluid from the mother’s womb)

Babies grow and develop in an amniotic sac in the uterus in the mother’s womb. This fluid, in which the baby (fetus) in the mother’s womb floats, is called the amniotic fluid and the procedure of taking a sample from this fluid is called Amniocenteses. Some information is obtained about the health of the baby by investigating this fluid. It is used in the detection of certain diseases. Amniocenteses can be colloquially referred to as “taking a sample of amniotic fluid from the mother’s womb”. The amniotic fluid, in which the fetus floats, is accessed inserting a needle through the abdominal skin of the expectant mother and a specific amount of water is drawn. However, this procedure results in a miscarriage in about one among 200 to 300 pregnant women. Therefore, it is not recommended to all pregnant women, a decision is made together with the family taking the possibility of a disease into consideration.

Why is amniocenteses performed by your doctor:

Amniocenteses is mostly performed to diagnose some diseases and disorders in the fetus.

Advanced maternal age (the probability of delivering a diseased child increases in all expectant mothers that are at the age of 35 and over and such probability rules out the risk of possible loss of the baby resulting from amniocenteses. Amniocenteses procedure was recommended for this reason. Nowadays the prevalant approach is to perform amniocenteses if an increase in risk is identified based on sreening tests and ultrasound results instead of age limit.)

History of  previous delivery of a child with a chromosomal disorder (a disabled child) or identification of a chromosomal disorder in the previous miscarriage (Performance of amniocenteses is recommended due to probability of recurrence to a certain extent).

Existence of a genetic disease, chromosomal disorder in the pregnant woman or her husband or a close relative that can be diagnosed with amniocenteses (Performance of amniocenteses is recommended due to the probability that it might have passed to the baby).

If a risk increase has been identified as a result of the early screening test called the double test performed between the 11th and 13th weeks but chorionic villus biopsy could not be performed for some reason, amniocenteses is recommended.

If the risk revealed as a result of the screening test which is called a Triple Test is higher than the risk the procedure of amniocenteses itself carries. For example, a pregnant woman has a triple test in the 16th week and the risk calculated for Down Syndrome is reported to be 1/200. This means the possibility of the fetus carried out by that pregnant woman to have Down Syndrome is 1/200. If the family accepts amniocenteses, amniocenteses will definitely show whether this risk exists or not. However, it should not be forgotten that in this case the family will have accepted a medical procedure, in which the fetus might be lost due to miscarriage with a probability of 1/200. Here, it is the decision and responsibility of the family. Your doctor informs you about these risks and lets you decide.

It is recommended that you have it if a problem is detected in the fetus during the ultrasound examinations and if it is considered necessary.

To detect some inherited metabolical diseases.

Amniocenteses procedure might also be recommended in the advanced months of the pregnancy under the following special cases:

• To understand the degree to which the fetus will be affected by blood group (Rh) incompatibility
• To understand whether there is inflammation in the amniotic fluid
• To identify whether the lungs of the fetus is developed enough to survive in the external environment

When and how is amniocentesis performed: Amniocenteses is usually performed between the 15th and 20th weeks, optimally between the 16th and 18th weeks. Early amniocenteses performed in an earlier period is not much recommended due to its risks. In the advanced months of pregnancy, on the other hand, it might be performed for other medical reasons. However, it is not very useful in detecting chromosomal disorders when it is performed after the 20th gestational week.

Amniocenteses is a procedure carried out by an obstetrician and gynecologist which can be considered to be painless for the mother. A needle is inserted into the abdomen of the mother under ultrasound examination and a specific amount of (about 15-20 ml) is taken from the amniotic fluid, in which the fetus floats, with an injector. The procedures lasts for a short time. The practice is ended by controling the condition and heartbeats of the fetus again with an ultrasound. The pregnant woman is relaxed for some time and usually sent back home on the same day. Sometimes your doctor may ask you to stay longer to relax. The fluid taken is usually conveyed to the laboratory via the health institution or patients relatives in two separate tubes or injectors. Results of the amniocenteses performed to detect hereditary diseases are reported by the laboratory in 3-4 weeks. Laboratory techniques that give results faster, in a few days, are also available for specific diseases.

If blood group (rH) incompatibility is present in the pregnant woman, on whom an amniocenteses has been performed, she must have an injection for preventing blood incompatability (Anti Rh D immunoglobulin) after the procedure. This injection will be prescribed by your doctor.

Risks Arising From The Amniocenteses Procedure

Pregnancy Loss (Miscarriage): The probability is very low, about 1/200-300. The fetus lost might be a diseased fetus but it can be a wholly healthy fetus, too.

Infection: This is very rare. Usually displays symptoms in the first 3-5 days. Such complaints as fever, chill, shivering, pain, sharp spasms etc are present. You must consult your doctor as soon as possible.

Bleeding or fluid leakage from the reservoir in the pregnant woman: Develops quite rarely but it is a situation that requires the pregnant woman to consult a doctor immediately.

Spasms in the pregnant woman: Can be observed during amniocenteses or in a short period of time after the amniocenteses. Existence thereof alone and without any other additional complaints is not very significant but you are recommended to contact your doctor to have the situation explained.

Injury to the fetus: the risk is very low but present. sk çok azdır, ancak vardır.

How are the results of amniocenteses interpreted?

It gives results with respect to diseases that can be detected via amniocenteses. The fetus might be healthy or the suspected diagnosis of the disease becomes definite. Very rarely might there be problems that mniosentez ile tespit edilebilen hastalıklar açısından bir sonuç verir. Bebek sağlıklı olabilir veya şüphe edilen hastalık tanısı kesinleşir. Çok nadiren Test sonucunda karar vermeyi engelleyecek sorunlar olabilir. Alınan sıvıdaki hücreler laboratuar ortamında gelişmez, bu durumda sonuç da değerlendirilemez. Başka tetkikler gerekebilir.

Not all kind of diseaes can be diagnosed via amniocenteses. It provides information about chromosomal disorders and some diseases. Although the announcement of the result as normal does not show that the fetus is health in all respects, it shows that the fetus is health with respect to specific frequent diseases. Therefore, there is a statement beneath the laboratory results saying that some diseases (such as structural disorders) cannot be detected and that the result cannot show that the fetus is healthy in this respect.

Cordosentesis (Removal of some blood from the umbilical cord)

The fetus receives its nourishment from the mother’s blood via the placenta inside the uterus. The contact between the fetus and the placenta takes place through veins called the umbilical cord. There is the fetus’s blood in the umbilical cord. Cordosentesis is removal of the blood that belongs to the fetus from the umbilical cord by entering through the mother’s abdominal wall. The blood removed is sent to the laboratory to carry out various investigations relating to the health of the fetus.

Why is cordosentesis performed by your doctor:

Just like amniocenteses, cordosentesis is performed to detect some diseases and disorders of the fetus. It can usually be carried out after the 20th gestational week. The most important advantage of corodsentesis is that it makes it possible to make a diagnosis in a short period of time like a few days in advanced gestational weeks.

Genetic Research: Is performed to identify the chromosomal structure (karyotype) of the fetus. Family’s delayed consultation, failure of previously performed prenatal diagnosis methods or obtainment of suspicious results are the reasons why it is performed.

To detect some hereditary blood and metabolic diseases.

It is recommended that you have cordosentesis if a problem is detected during ultrasound examinations cordiosentesis is considered to be necessary.

To research some infections.

To understand the extent to which the fetus will be affected by blood group (Rh) incompatibility and for the treatment (blood transfusion to the fetus) if necessary.

To assess the medical condition of fetuses with growth deficiency.

When and how is cordocentesis performed:

Cordocentesis is usually performed after the 20th gestational week. It is performed in a manner that is similar to the amniocentesis procedure. The difference is that the blood of fetus is drawn instead of the amniotic liquid. In codocentesis, a special needle is inserted into the abdominal wall of the mother under ultrasound control drawing a specific amount of blood that belongs to the fetus through the umbilical cord and it is sent to the laboratory so that various investigations can be carried out about the health of the fetus. Condition and heart beats of the fetus are checked with an ultrasound again after the procedure. The pregnant woman is related for some time and is usually sent back home on the same day. Sometimes your doctor might ask you to stay longer so that you can relax. A relaxation of 1-2 days is recommended after the procedure.

If there is blood group (Rh) incompatibility in the pregnant woman going through cordocentesis, an injection to prevent blood incompatibility (Anti Rh D immunoglobulin) must be given to her after the procedure. The injection will be prescribed by your doctor.

The results are obtained in about a week if the cordocentesis is carried out to detect hereditary diseases but if it is carried out for another reason, the time on which the results will be obtained will change depending on the reason.

Risks arising from the cordocentesis procedure:

Cordocentesis incluses more serious risks when compared to the other prenatal diagnosis methods. Therefore, it is performed in centers that are experienced on this matter only.

Fetus: Damage to the umbilical cord, slowing on heartbeats, preterm delivery, fetus death can be observed. Probability of loss of the fetus due to complications (unavoidable disappointing results) in general is 1%.

Risk for the mother might be bleeding or fluid leakage from the reservoir. Another risk is infection. These probabilities are very low. However, if complaints like fluid leakage or fever, chilling, shivering, pain, severe spasms still occur, you must consult your doctor as soon as possible.

Chorionic Villus Sampling (CVS)

In the mother’s womb, the fetus takes nourishment from the mother’s blood through an organ called placenta in the uterus. The procedure of tissue sampling from the placenta of the fetus to make a genetic diagnosis is called Chorionic Villus Sampling (abbreviated as CVS). It is usually performed by entering the uterus from the abdomen. It can rarely be performed vaginally. Its most important advantage is that it makes it possible to make a diagnosis before the pregnancy advances as it is performed in the early weeks of pregnancy. If a problem is detected in the fetus, an earlier intervention can be performed. Simpler and safer methods can be implemented to terminate the pregnancy. Its disadvantage is that prevalance of complications (unavoidable disappointing results) such as the risk of miscarriage, bleeding and spasms is a little higher compared to amniocenteses.

Why is chorionic villus sampling is performed by your doctor:

It is a prenatal diagnosis method. It gives the chance to notice some congenital diseases in the mother’s womb. It is usually performed for the same reason as amniocenteses.

Advanced maternal age (The risk of delivering a diseased child is higher in these pregnancies. See the Amniocenteses section for a broader explanation).

History of delivery of a child with chromosomal disorders (a disabled child) or detection of this in the previous pregnancy (Recommended as there is a risk okf repetition to a certain extent).

Presence of a genetic disorder, chromosomal disorder in the pregnant woman or his husband or a close relative (Recommended due to the probability that it will pass to the fetus).

If it is considered to be necessary as a result of the early screen test called the double test performed in the 11th to 14th weeks.

Recommended if a problem is detected in the baby during the ultrasound examination and if it is considered necessary.

When and how is Chorionic Villus Sampling performed:

Chorionic villus sampling is best performed between the 11th and 13th weeks of pregnancy. A very small amount of tissue is taken from the parts called villus of the placenta in the uterus by entering through the mother’s abdominal wall with a special needle under ultrasound control or through the vagina (reservoir) with a suitable plastic tubule. The villus is sent to the laboratory for various examinations relating to teh health of the baby. This procedure is usually painless. Condition and heartbeats of the fetus are checked with an ultrasound again after the procedure. The pregnant woman is relaxed for some time and is usually sent back home on the same day. Sometimes your doctor might ask you stay longer for you to relax. Relaxation of 1-2 days is recommended after the procedure.

An injection for preventing blood incompatibility (Anti Rh D immunoglobulin) must be given to the pregnant woman if she has blood group (Rh) incompatibility). The injection will be prescribed by your doctor.

The results of this diagnosis procedure, which is performed in the earlier weeks of pregnancy compared to amniocenteses, are also obtained earlier.

Chorionic villus sampling results have a whole heap of reliability in identifiying some chromosomal disorders and special genetic problems. However, results might sometimes be inadequate or uncertain. In that case amniocenteses might be required to understand the condition of the fetus.