2023-06-02 08:00:17
It is estimated that one in ten women has had or will have a miscarriage. Whether early or later, this sudden termination of pregnancy is a difficult time for the couple. Among their questions, the question of the cause of the miscarriage comes up very often. A Danish study sets out to provide answers to this question, thanks to a simple maternal blood test. Explanations.
What causes miscarriages?
THE miscarriages are by far the leading cause termination of pregnancy. What are the causes ? In more than half of the cases, and especially for early miscarriages, abnormalities in the development of the embryo explain the occurrence of the miscarriage. These abnormalities may be genetic (abnormalities in the chromosomes) or related to Embryonic development.
Sometimes miscarriages can be related to maternal pathologiesas :
- Poorly controlled diabetes;
- Thyroid pathologies;
- Hormonal disorders;
- Autoimmune diseases, such as lupus;
- Blood clotting disorders;
- celiac disease;
- Abnormalities of the cervix or uterus.
A simple blood test to understand the cause of the miscarriage?
Other factors can cause a miscarriage, early or later, such as certain viral (cytomegalovirus), parasitic (toxoplasmosis) or bacterial (listeriosis) infections, exposure to toxic chemicals or even taking certain medications that are contraindicated during pregnancy. Finally, maternal age and history of miscarriage with the same partner are risk factors for miscarriage. To be able to answer the question of the origin of miscarriage, Danish researchers conducted a prospective cohort study. Previous studies had revealed that the analysis of the nucleus of fetal cells (detection of chromosomal abnormalities) could make it possible to explain the miscarriage and to predict the risk of another miscarriage or, on the contrary, of a pregnancy carried to term. But the analysis of the nucleus requires the removal of fetal tissue, a complex sample to perform routinely.
In this new study, the researchers used the small fraction of fetal DNA which circulates in the maternal blood. From this DNA, they can assess the state of the nucleus of the cells of the embryo. For the first time, this method has been validated on a large scale on 1,000 adult women, admitted to 3 Danish clinics between November 2020 and May 2022, presenting with a miscarriage before the gestational age of 22 weeks.
A possible explanation for nearly half of miscarriages
At the time of the miscarriage, the gestational age of the fetus ranged from 35 to 149 days. The results collected on the fetal DNA present in the maternal blood were able to reveal the existence of chromosomal abnormalities with a sensitivity of 85% and a specificity of 93%. Of all the miscarriages taken into account, the state of the nucleus of the fetal cells made it possible to explain the termination of pregnancy in nearly half of the cases.
This new study reveals that a analysis you sang maternal in the hours following the miscarriage could help explain the chromosomal abnormalities involved in a certain proportion of miscarriages. A simple blood test could thus offer the possibility of implementing preventive treatments. This possibility could only apply from the fifth week of pregnancy, since no trace of fetal DNA is present in the maternal blood before this term. So there is still a long way to go to explain all the miscarriages!
Estelle B., Doctor of Pharmacy
Sources
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