First trimester
First trimester diagnostics
First trimester diagnostics can be carried out between weeks 11+1 and 13+6 of pregnancy, i.e. at the end of the first trimester. The 12+0 to 13+0 weeks of pregnancy is usually the best possible time for the examination due to the ultrasound conditions. In a so-called first trimester screening (ETS), an early organ examination, a nuchal translucency measurement and a laboratory test are carried out for the early detection of Pre-eclampsia made.
ETS is not part of the regular screening for normal pregnancies, so the costs for these examinations are not covered by statutory health insurance.
Early organ examination
A comprehensive ultrasound examination is at the centre of first trimester diagnostics. This examination allows contact to be established with the unborn child at an early stage of pregnancy, making it possible to make statements about its development.
However, early organ diagnostics also has its limits: An unremarkable finding is never a guarantee of a healthy child. In addition, early ultrasound does not allow any conclusions to be drawn about any chromosomal abnormalities, for example.
Risk calculation for trisomy through nuchal translucency measurement
In order to be able to make a probability statement about the risk of a trisomy of chromosomes 13, 18 or 21, we determine the nuchal translucency (nuchal fold) of your unborn child using an ultrasound scan - if you wish. We can also arrange for a hormone test of the mother's blood to calculate the risk of trisomy.
We can achieve even more certainty if you have a chromosome analysis of the foetal cells carried out.
Normal human chromosome set
The risk determined after the examination is given as a ratio. Let us give you an example: If the risk of having a child with Down's syndrome is given as a ratio of 1:500, this means that for every 500 pregnant women with the same risk, one woman will have a child with Down's syndrome: For every 500 pregnant women with the same risk, one woman will have a child with Down's syndrome. In the table below you can categorise your result in relation to the pure age risk.
(for a 12-week pregnancy)
| 20 years | 1 : 1068 |
| 25 years | 1 : 946 |
| 30 years | 1 : 626 |
| 32 years | 1 : 461 |
| 34 years | 1 : 312 |
| 36 years | 1 : 196 |
| 38 years | 1 : 117 |
| 40 years | 1 : 68 |
| 42 years | 1 : 38 |
| 44 years | 1 : 21 |
We recommend a chromosome analysis from amniotic fluid or chorionic villi from a determined individual risk of 1:100 or worse. Only a chromosome analysis can reliably recognise pregnancies with trisomies.
If a widened nuchal translucency is detected during a first trimester diagnosis, this can have very different causes: In addition to a suspected trisomy, the causes can also include heart defects, skeletal malformations or metabolic defects and diaphragmatic/umbilical hernia.
However, if the chromosome findings due to a widened nuchal translucency remain unremarkable, targeted examinations such as an organ ultrasound should be carried out before the 20th week of pregnancy to rule out other possible causes of a widened nuchal translucency.
Sometimes a widened nuchal translucency can occur in completely healthy children without any recognisable cause. The pregnancy then also proceeds without complications.
The risk calculation procedure is based on certain guidelines and framework conditions. These are specified by the FMF-London (FMF = Fetal Medicine Foundation). The FMF-London has set itself the goal of offering all interested pregnant women standardised prenatal diagnostics with first trimester diagnostics at an early stage of pregnancy.
As an FMF-certified practice, we meet the highest quality standards. WWW.FETALMEDICINE.COM.
According to the Genetic Diagnostics Act (GenDG), which has been in force since February 2010, an ultrasound examination with subsequent risk calculation is also a genetic examination. The doctors carrying out the examination are therefore obliged to do so:
- to inform you about the examination
- Offer you genetic counselling
- to provide you with information material.
Questions or appointments?
Do you have further questions about "First trimester diagnostics" or would you like to make an appointment at our practice for prenatal medicine and genetics?
Early detection of pre-eclampsia
The risk of pre-eclampsia can also be determined as part of first trimester diagnostics. If a high risk of pre-eclampsia in the expectant mother is recognised early, preventative measures and appropriate check-ups can be arranged.
Pre-eclampsia - what is it?
Pre-eclampsia is a complication that can occur during pregnancy. Typical symptoms are high blood pressure, protein excretion in the urine and water retention in the tissue. In many cases, there is also hypofunction of the placenta.
On average, around one in 100 women develops pre-eclampsia during pregnancy. If a severe and early form of pre-eclampsia occurs, labour must be induced before the 35th week of pregnancy to protect the mother and child. Statistically speaking, around one in 200 pregnant women develops severe pre-eclampsia.
Pregnancies with a high risk of pre-eclampsia can now be recognised early thanks to the latest tests. If a high risk of pre-eclampsia has already been recognised in the first half of the pregnancy, the doctors looking after you can take appropriate preventative measures and arrange check-ups. We therefore recommend that the pre-eclampsia risk test is carried out at the same time as the First trimester screening or one early organ diagnostics possibly in combination with a non-invasive foetal DNA test (NIPT) to be carried out.
We require the following information for an examination for pre-eclampsia risks:
- Blood pressure measurements on both arms
- Doppler measurements in the arteries supplying the uterus
- Information on any previous pregnancies
- Information on health history
- Height and weight
- PlGF and PAPP-A value (also measured during first trimester screening to calculate the trisomy risk)
A precautionary intake of acetylsalicylic acid (ASA) is currently recommended for a personal risk of one in 100 or worse. In addition, a blood coagulation test may also be useful in individual cases.
