Maternal-Fetal & Perinatal Medicine

In the majority of cases, it is performed transabdominally. It is carried out at a specific time frame in the period of pregnancy (gestational age between 11 weeks and 1 day to 13 weeks and 6 days), having as an aim:

• The confirmation of the gestational age, especially in cases of women taking contraceptives, with irregular cycle and incorrect reports of their last period.
• The diagnosis of multiple pregnancy and the determination of chorionicity.
• The diagnosis of basic fetal anomalies.
• The determination of the risk of the fetus suffering from a chromosomal abnormality (e.g., Down syndrome).

What is nuchal translucency?

In every fetus, fluid is collected at the back of their neck, between the muscles and the skin. This presence of fluid is called nuchal translucency. The greater the nuchal translucency, the greater the risk that the fetus is suffering from a chromosomal abnormality or other problems (genetic disorders, congenital heart diseases).

In this ultrasound, we are also looking at a number of ultrasound markers such as:

• the presence of the nasal bone, as in a large percentage of fetuses with Down syndrome and genetic disorders, it has not yet developed at this gestational age,
• the blood flow in the ductus venosus and in the heart’s tricuspid valve, which are abnormal in fetuses with chromosomal abnormalities and congenital heart diseases.
  

At the same time, we are checking two biochemical markers in the mother's blood (hormones produced by the placenta), PAPP-A and free beta-HCG, which have been shown to be at different levels in the blood of mothers carrying normal fetuses and different in fetuses showing abnormalities.

The level II ultrasound is performed transabdominally from the 20th to the 24th week of pregnancy with the aim of:

• Screening the fetal anatomy and echocardiography in detail, in order to rule out, as far as possible, congenital malformations.
• Checking for smooth intrauterine growth, determining the position of the placenta and assessing the amniotic fluid.
• Checking for the presence of any anatomical markers that increase the risk of chromosomal abnormalities in the fetus.
• The assessment of the blood flow in the uterine vessels in order to establish the adequate perfusion of the placenta and to assess the possibility of the risk of residual intrauterine growth or preeclampsia.

In addition, a transvaginal ultrasound is performed to assess the cervix to determine the risk of preterm labor based on its length. Transvaginal ultrasound is particularly important for women at high risk for preterm birth (multiple pregnancies, history of preterm birth in a previous pregnancy, anatomical abnormalities of the uterus, history of cervical surgery). 

It is usually carried out between the 28th and 32nd week of pregnancy and a significant percentage of abnormalities that are not detected sonographically in the two previous ultrasounds can be detected by performing it. At the same time, it is deemed necessary if complications occur (preeclampsia, gestational diabetes, intrauterine growth restriction).

Its purpose is to inspect the development of the fetus, the amniotic fluid, the morphology and position of the placenta, the movements of the fetus and the uteroplacental blood flow.

During the aforementioned ultrasounds, the heart of the fetus is examined, however, a specialized examination by a pediatric cardiology specialist (diagnosis and consultation on the progression of the condition) is required when:

• The pregnant woman has a family history of heart disease, or diabetes mellitus, or is being treated with antiepileptic medication.
• When during the 1st trimester ultrasound, the fetus has: increased nuchal translucency, retrograde flow in the tricuspid valve, increased resistance in the ductus venosus, or, during the level II ultrasound: anatomical abnormalities, suspected congenital heart diseases.

In recent years, it has been discovered that a blood sample of the mother after the 10th week of pregnancy contains 5-10% fetal blood.

Non-invasive prenatal testing is the test in which, with a simple blood draw from the mother, we examine the genetic material (DNA) of the fetus that circulates freely (apart from cells) in the mother's blood (prenatal cell-free DNA screening). Thus, by using sophisticated methods, we can detect in high percentages: Down syndrome 99%, Edwards syndrome and Patau syndrome, sex chromosome aneuploidies (Turner syndrome, Klinefelter syndrome, Triple X syndrome, Jacob’s syndrome, XXYY syndrome), microdeletion syndromes (DiGeorge syndrome, 1p36 deletion syndrome, Cri-du-Chat syndrome, Prader-Willi syndrome, Angelman syndrome, 22q11.2 deletion syndrome, Smith-Magenis syndrome, Wolf-Hirschhorn syndrome), 50 monogenic disorders (An oral swab from the biological father is required).

Of course, an ultrasound examination of the fetus is always required to rule out structural abnormalities and markers of chromosomal abnormalities, and also a consultation by a genetic counselor.

We recommend it mainly for women at medium-risk, where we want something more potent than the wide-scope 1st trimester ultrasound (nuchal translucency) but the above findings are absent. It can also be offered to any pregnant woman who simply wishes to do so without belonging to any of the above groups.

It is important for the couple to know that the test is not diagnostic, and in case of a positive result, invasive testing is recommended, through chorionic villus sampling or amniocentesis, to confirm the diagnosis.