Perinatology

In the Department of Obstetrics and Gynecology, Division of Perinatology at Yeditepe University Hospitals, studies are carried out for the follow-up and management of high-risk pregnancies, in addition to routine pregnancy follow-up and the delivery process. In the diagnosis and management of maternal and fetal diseases, the pregnancy process is evaluated in detail by utilizing various tests, examinations, and interventions.

What Is Perinatology?

Perinatology is a field concerned with the evaluation of the mother and fetus during pregnancy, the follow-up of pregnancy, and the diagnostic and management processes to be applied when necessary. In addition to routine pregnancies, the follow-up and management of high-risk pregnancies are also addressed within this scope.

What Does Perinatology Deal With?

In the Division of Perinatology, various procedures and tests are performed for routine pregnancy follow-up and delivery, the follow-up and management of high-risk pregnancies, and the diagnosis and management of maternal and fetal diseases:

•  11-14 weeks scan tests.

•  15-21weeks scan tests

•  11-14 weeks transvaginal detailed fetal anomaly screening (detailed perinatal examination)

•  18-22 weeks obstetric detailed anomaly screening (detailed perinatal examination)

•  Fetal echocardiography

•  Maternal and fetal Doppler ultrasonography examinations 

• Corionvillus sampling (CVS)

•  Amniocentesis

•  Fetal blood sampling (Cordocentesis)

•  Embryo reduction

•  Selective fetal reduction 

•  Feticide administration

 Down Syndrome Screening Tests

Individuals with Down Syndrome have three copies of chromosome 21, instead of the usual two copies, in all cells. It is also known as Trisomy 21. It is a syndrome that usually progresses with intelligence problems and heart disease. It occurs approximately once in 700-800 pregnancies. As the age of the mother increases, the incidence of this syndrome increases as well. For instance, it occurs once in 280 births at the age of 36 and once in 100 births at the age of 40. Since it is the most common chromosomal anomaly in society, it is recommended that all pregnant women be screened for Down syndrome. This scan is performed in two ways:

Ultrasonographic fetal nape transparency test between the 11th-14th weeks of pregnancy:

The fetal nape transparency test is a simple test performed by ultrasonography between the 11th and 14th weeks of pregnancy. In the appropriate position, the nape thickness of the baby is measured and compared with the normal ones in the computer environment. The purpose of this test is to make us suspect some chromosomal disorders and heart diseases in the early period. The ultrasonographically performed fetal nape transparency test, if biochemical tests are added, ensures that an average of 90 percent of babies with Down syndrome are suspected and recognized early. Moreover, the evaluation of features such as the presence of fetal nasal bone added to the screening program for 11-14 weeks in recent years, some blood flow characteristics in the fetal heart and circulation, and facial angle provides a better evaluation of the current risk for Down Syndrome. If a high risk is detected as a result of the 11-14 week screening test, a chorionic villus biopsy is recommended for further examination.

Triple or quadruple test between 15-21 weeks of pregnancy:

The triple or quadruple screening test is a simple test that takes maternal blood between the 15th and 21st weeks of pregnancy. When evaluating the test result, the mother's age, race, weight, family history, presence of diabetes, smoking status, gestational week, and some hormones secreted by the mother and baby are taken into consideration. The test accuracy is 60-80% on average. A positive or high-risk test does not indicate that the baby is sick, only that diagnostic tests should be used for definitive diagnosis. These are done by taking samples from the fluid in the womb (uterus) or blood. The negative result of the test does not show that the baby is not sick, only that the risk of Down syndrome is low. If a high risk is detected in the triple test/quadruple test, it is recommended to perform amniocentesis or cordocentesis for further examination.

Amniocentesis

Amniocentesis is the process of removing a maximum of 15-20 ml of fluid from the fluid-filled amniotic cavity of the fetus with needles between 9-15 cm, which is usually applied for the diagnosis of fetuses at risk of chromosomal abnormality between the 16-22 weeks of pregnancy. No additional local or general anesthesia (numbing medication) is required. Following the ultrasonography examination, the skin is cleaned and the sterile needle is advanced into the abdominal layers from a section that will not harm the fetus. The amniotic fluid is aspirated as much as necessary in accordance with the gestational week and sent to the laboratory. The standard result time (cell culture) usually varies between 18-25 days. In addition, Fluorescent in situ hybridization (FISH) analysis can be learned within 24-72 hours as a result of the preliminary examination of chromosomes 13, 18, 21, X, and Y.

There is a 0.5-1% risk of losing the fetus after amniocentesis. There may also be 2% mild bleeding or water discharge. There is rarely a risk of developing a pelvic or systemic infection after the procedure. If there is insufficient reproduction in the cell culture after the first attempt, it may be necessary to repeat the process.

Chorionic Villus Sampling (CVS); 

Chorionic villi sampling is the process of biopsy tissue removal from the placenta of the fetus with needles between 9-15 cm, usually applied for the diagnosis of fetuses at risk of chromosomal abnormality between the 11th and 14th weeks of pregnancy.
Additional local anesthesia (numbing medication) is usually required. Following the ultrasonography examination, the skin is cleaned and the sterile needle is advanced into the abdominal layers from a section that will not harm the fetus. With the help of an injector, the villi are aspirated as needed and sent to the laboratory. The standard result time usually varies between 14-16 days. The result is obtained as a 95% rate, %1 may not be cell reproduction, and 1-5 percent may be maternal contamination. In such a case, 16-18, it is necessary to undergo an amniocentesis procedure in weeks. The genetic result shows chromosome number and structure abnormalities and does not provide information about other genetic diseases. 
After this procedure, there is a 1% risk of losing the fetus. There may also be 2% mild bleeding or water discharge. 

Cordocentesis

Cordocentesis is the process of taking a maximum of 2-3 ml of blood from the cord vein of the fetus with needles between 9-15 cm, usually applied for the diagnosis of fetuses at risk of chromosomal abnormality after the 19th week of pregnancy. Following the ultrasonography examination, the skin is cleaned and the sterile needle is advanced into the abdominal layers from a section that will not harm the fetus. Using a sterile syringe, the fetal blood is aspirated as needed and sent to the laboratory. The standard result time usually varies between 14-16 days. There is a 1% risk of losing the fetus after cordocentesis. There may also be a 2% risk of mild bleeding or water discharge and premature birth. There is rarely a risk of developing a pelvic or systemic infection after the procedure.

Obstetric Detailed Anomaly Scan

During pregnancy, some examinations are performed with ultrasonography to identify possible problems with the fetus and to take precautions accordingly. The objectives of the evaluation of the fetus by ultrasonography can be listed as follows: Determination of the age of the fetus, evaluation of the development and growth of the fetus, examination of fetal anatomy, detection of life-compatible fetal anomalies, and preparation for postpartum treatment by preparing appropriate birth conditions and detection of fetal anomalies that are incompatible with life and offering the possibility of terminating a pregnancy to the family within legal limits.

Although it is not a routine practice all over the world, some countries perform “Obstetric Detailed Anomaly Scanning” or “Detailed Perinatal Examination”, also called 2nd level ultrasonography or anomaly scanning. Here, using ultrasonography devices with advanced technological equipment and very high resolution, it is investigated whether the fetal organs continue their normal development during a certain gestational week, whether an anomaly occurs in the formation of organs, and whether there are important ultrasonographic markers for chromosomal abnormalities in the fetus.

Although approximately 60-65% of major fetal anomalies are detected before 22 weeks of pregnancy, some brain, vision, and hearing defects, eye and ear abnormalities, skin and nerve diseases, heart valve diseases and small holes in the heart, gland diseases, vascular problems, unspecified pharyngeal, intestinal, kidney, rectal obstructions, gender disorders, hip dislocation, subtle bone shortness, small abnormalities in the fingers and toes, and some chromosomal disorders and rare genetic syndromes cannot be visualized and recognized early during scans. Along with the following weeks of pregnancy, some abnormalities that have not been seen before may occur in the fetus. This can be noticed only in the periods after birth. For this reason, continuity of examination is essential in high-risk pregnant women.

During this examination, in addition to the above, blood flow measurement to the placenta (Uterine Artery Doppler) and blood flow measurements in other veins of the fetus and cervical length measurement (Cervical Evaluation) can be performed in risky pregnant women. What is essential in "Obstetric Detailed Anomaly Screening" is that this application is performed in appropriate weeks of pregnancy (18-22 weeks), using high-resolution ultrasonography devices, and applied by trained specialists in this regard.
Equivalent to this examination, definitions such as Color Doppler, Three-four-dimensional ultrasonography, and Color ultrasonography are also frequently used. Such definitions only indicate the characteristics of the device and are used as a false terms by patients and/or doctors.
Color Doppler or Color ultrasonography is a method of ultrasonography that only allows early recognition of blood circulation problems in the fetus and mother and early taking of necessary precautions and evaluates blood flow measurements in the blood flow to the placenta and other veins of the fetus. Almost all of the devices used in Obstetric Detailed Anomaly Scanning are color ultrasonography devices.

Three-four-dimensional ultrasonography, on the other hand, is a method that generally provides colored imaging of the face and other organs of the fetus, resembles color photography, has not been widely used scientifically, and is used for aesthetic and commercial purposes. Routine use in Obstetric Detailed Anomaly Screening or routine pregnancy ultrasonography has no place.

Fetal Echocardiography

newborns. Congenital heart disease is 6.5 times more common than chromosomal abnormalities. Although congenital heart disease is such an important health problem and the most common anomaly, it is the most frequently overlooked anomaly during ultrasonography.

Fetal heart examination can be performed by 3 different methods. Basic screening is performed by evaluating the 4-chamber of the heart and detailed basic screening is performed by evaluating the 4-chamber and large vessels. Basic screening and detailed basic screening is an examination methods that should be applied to all pregnant women.
In fetal echocardiography, a detailed analysis of cardiac structure and function is performed and advanced sonographic techniques are used.

Fetal echocardiography is not applied to all pregnant women but is applied when the risk of congenital heart disease is high or when a heart abnormality is suspected in a basic scan or detailed basic scan. Patients with an increased risk for congenital heart disease can be summarized as follows:

• Presence of congenital heart disease in mothers, fathers, and other siblings, 

• Suspicion of congenital disease other than heart disease in the baby, 

• Presence of diabetes in the mother, 

• Mother’s use of medication for epilepsy, 

• Inadequate visualization of the baby's heart or suspicion of heart disease by the obstetrician, 

• In the 11-14 week ultrasonographic nuchal fold thickness test, (the measurement of the nuchal fold thickness is above the 95th percentile according to the gestational week or above 3.5 mm regardless of the gestational week) 

• Acceleration and slowing of the baby's heart rate (fetal heart rhythm disorders).

Fetal echocardiography can be performed ideally at the 18th-21st gestational week; always done after the 14th week. Although the study takes 15-30 minutes, it may take longer depending on the placement of the baby and the clarity of the image. Sometimes it may be necessary to do more than one examination.

During this examination, due to the gestational week, posture, overweight mother, and insufficient image quality, the rate of fetal echocardiography to detect congenital heart diseases is around 85-90%. Among the reasons for this are that some diseases become diseases after birth and some deformities are progressive. Some diseases that are detected may also disappear until birth.

Thanks to fetal echocardiography, information can be obtained about which fetus should be intervened early and which should be left after birth. In addition, the center where the birth will be performed is selected in this way. While a baby with heart disease that will be corrected long after birth is delivered under normal conditions, those requiring immediate surgery can be referred to hospitals with cardiology units, and the chance of survival of the baby after birth can be increased.