MISCARRIAGE DIAGNOSTICS

Recurrent miscarriages, defined as two or more pregnancy losses before the 24th week, affect 2-3% of women of reproductive age. These losses often cause significant psychological distress for the parents. Understanding the causes is important for both coping and assessing the risk of recurrence.

Request Test

  • Specimen: Miscarriage tissue and maternal EDTA blood sample
  • Examination method: Array-CGH in combination with STR marker analysis
  • Turnaround time: approx. 2 weeks
  • Required documents:

Detailed information on sample submission can be found here.

GENERAL INFORMATION

Approximately 80% of all pregnancy losses occur in the first trimester (the first 12 weeks) of pregnancy, with chromosomal maldistributions being the most common cause. While maldistributions of entire chromosomes (trisomies and monosomies) as well as entire sets of chromosomes (triploidy and tetraploidy) are associated with a relatively low risk of recurrence, structural chromosomal aberrations are found in one partner in 2-5% of couples with recurrent miscarriages. These couples have a significantly increased risk of further pregnancy losses.

In accordance with the guidelines of the DACH societies (Germany, Austria, and Switzerland) for gynecology and obstetrics, HLN Genetik offers miscarriage diagnostics using array-CGH analysis. Additionally, a comparative STR analysis of maternal DNA and DNA isolated from the miscarriage tissue is performed to ensure that the examined material is indeed of fetal origin.

Diagnostics

According to the recommendations of the DACH societies, array-CGH analysis is used to clarify the cause of a miscarriage. Classical chromosome analysis is not performed, as it requires viable or dividing cells. However, in many cases, dividing cells cannot be obtained, especially if the fetus has been deceased for a longer period (IUFD). Often, the quality/resolution of chromosomes obtained from miscarriage material is low, so only numerical or larger structural changes (10-20 Mb) can be detected on the chromosomes. Another disadvantage of classical chromosome analysis is that if a female karyotype is detected, it cannot be distinguished whether the examined metaphase is actually of fetal or maternal origin. According to literature, this affects up to 20% of examinations with a female karyotype.

The clarification of pregnancy loss is carried out in two steps. First, DNA is isolated from the miscarriage tissue and a maternal sample. Only if it is ensured by STR analysis that the material is indeed of fetal origin, the second analysis step using array-CGH is performed.

The combined STR and array examination can detect the following changes:

  • numerical chromosomal changes (trisomies, monosomies, triploidy)
  • chromosomal mosaics >20%
  • microduplications (>500 kb)
  • microdeletions (>500 kb)
Back