Age (Years)	Risk of trisomy of chromosome 21 (WG = weeks of gestation)
	At birth	At 12 WG
20	1 in 1527	1 in 1068
25	1 in 1352	1 in 946
30	1 in 895	1 in 626
31	1 in 776	1 in 543
32	1 in 658	1 in 439
33	1 in 547	1 in 383
34	1 in 445	1 in 297
35	1 in 356	1 in 249
36	1 in 280	1 in 187
37	1 in 218	1 in 152
38	1 in 167	1 in 112
39	1 in 128	1 in 89
40	1 in 96	1 in 64
41	1 in 73	1 in 51
42	1 in 55	1 in 36
44	1 in 30	1 in 20
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Dear Parents-to-be,

the majority of all children will be born in good health.

However, the following is true for almost all of them: family planning and pregnancy represent an intensive phase of emotions, wishes, hopes and also uncertainties. To assist you, we have summarised the possible prenatal pregnancy diagnostic procedures in this information leaflet and describe the possibilities and limits of these procedures. These measures can exclude or identify malformations and developmental disorders in the unborn child.

Before a planned examination, we first discuss all your questions in a personal consultation. Therefore please undersign the consent form for the planned examination after the consultation.

What are prenatal diagnostics?

All medical investigations which help to establish the state of health of the unborn child are included in prenatal diagnostics. The investigations exclude or identify malformations or developmental disorders in the unborn child.

The method chosen depends on the week of gestation (WG) and your age, family history and conspicuous ultrasound results. Treatment possibilities as well as diagnostics and advice are a part of the field of prenatal medicine even before the birth. Treatment which is necessary for the affected baby after the birth can be optimally planned before delivery where necessary. Personal consultations with the doctors who will look after the baby after delivery form a considerable part of this.

What are the causes of illnesses in the unborn baby?

Chromosomal abnormalities, genetic disorders and malformations are causes of illness in the unborn child.

CHROMOSOMAL ABNORMALITIES

Chromosomal abnormalities mean that there is a deviation in the number or structure of the chromosomes A human being normally possesses 46 chromosomes in each cell, 23 from the mother and 23 from the father. Every chromosome therefore exists as a pair. As a result of random errors when the cell divides, there can be one chromosome too many (three instead of two). This is given the name „trisomy“. Trisomy of chromosome 21, known as Down’s syndrome, is the most common abnormality. Small alterations in the makeup of the chromosomes can also affect the development of the unborn. There is a small risk of these random chromosome errors occurring in every pregnancy. Your family history and your own health have no influence over this. The risk of having a child with an abnormal chromosome count, especially Down’s syndrome (trisomy of chromosome 21), increases with your age.

At the start of pregnancy, the risk of a pregnancy with a chromosomal abnormality is naturally higher than at the time of birth, as pregnancies with a chromosomal abnormality– as planned by nature – often result in a
miscarriage.
The diagnosis of a chromosomal abnormality does not always reveal the degree of disability of the child.

GENETIC DISORDERS

Genetic disorders arise from mutations of genetic material. Generaly they are passed on in the family and follow a continuous inheritance pattern. As a result of new mutations, genetic disorders can also sporadically appear in people who until then had no family pathology. Genetic disorders can affect metabolic function as well as the body’s physical structure. Alterations in the genes which then lead to an inherited disease can normally only be discovered with specific diagnostic tests. If necessary, possible genetic disorders can be identified in the family history in a human genetic counselling session, together with advice about possible consequences. Some genetic disorders can be diagnosed prenatally with molecular genetics methods. In families who have no history of such disorders, prenatal diagnostic tests which look for certain illnesses are only rarely possible.

DEVELOPMENTAL DISORDERS

There are also illnesses or malformations of the unborn which are not connected with a chromosomal abnormality. The kidneys and urinary tract, heart and brain are most commonly affected. The causes of these malformations are often unknown. External influences such as medication, radiation effects or maternal infection are sometimes underlying.

Investigation methods in prenatal diagnostics

We offer a wide spectrum of prenatal diagnostics for the examination of your baby and for your safety. Alongside the most advanced technology, such as high resolution ultrasound and colour-Doppler techniques including 3D and 4D, a highly qualified practice team awaits you.

So that the examination is a reliable as possible, the desired investigations should be performed at an optimal time during pregnancy. When the investigation is possible from the 11+0 week of pregnancy for example, this means that it should take place in at least the 12th week of pregnancy.

Table (please click here)

Investigation	Optimum time	Aim
First trimester screening	12+0 - 13+0 WG	Risk estimation for trisomy 21
Chorionic villus sampling	From 11+0 WG	Chromosome examination, exclusion of trisomy 21
Amniotic fluid testing	From 14+1 WG	Chromosome examination, exclusion of trisomy 21
Triple-Test	From 15+0 WG	Risk estimation for trisomy 21
Alpha fetoprotein (APF)	From 15+0 WG	Risk estimation for neural tube defects
Umbilical cord blood sampling	From 18+0 WG	Chromosome examination, exclusion of trisomy 21
Differential organ ultrasound / echocardiography	19+0 - 20+6 WG	Exclusion and identification of malformations and development disorders
Doppler sonography	From 26+0 WG	Early recognition of developmental disorders
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