Spontaneously conceived low birth weight individuals and ARTs exposed to Vitrolife culture medium have a higher incidence of non-synonymous variants and rRNAs. A, b Prevalence of haplogroups and subhaplogroups, respectively, in SC and ART individuals exposed to Vitrolife culture medium, ranked according to their birth weight percentile. Two-sided Fisher’s exact test, no significant differences were found after Bonferroni correction (p values ≤ 0.007 were considered significant). vs Percentage of SC and ART individuals exposed to Vitrolife culture medium carrying homoplasmic variants in the different regions and classified according to their birth weight percentile. Homoplasmies in tRNA regions were more frequently found in children with birth weight
Claudia Spits, professor at VUB and member of the Reproduction and Genetics Research Group at Vrije Universiteit Brussel, has identified a genetic cause for the increased risk of low birth weight in babies born using birth control technologies. assisted reproduction such as IVF.
“Previous studies have identified treatment-related causes of low birth weight, but this is the first time we have managed to identify an underlying genetic factor,” says Professor Spits. She organized a large-scale study with Brussels IVF (the Center for Reproductive Medicine at UZ Brussel), the Center for Medical Genetics (CMG) at UZ Brussel and the University Medical Center Maastricht (UMC).
The article is published in Natural communications.
Initially, she studied the DNA of babies born from both spontaneous pregnancies and fertility treatment. She found that in both groups, a higher risk of low birth weight was associated with certain mitochondrial DNA mutations, and that these mutations were slightly more common in children born after fertility treatment.
Mitochondria are the “energy factories” of the cell inherited from the mother. If they do not function properly, as they develop, they can cause various health problems such as cardiovascular disease and diabetes.
To determine whether these mutations are passed from mother to child, the researchers also studied the mothers’ DNA. The analysis showed that children born after fertility treatment have more new, non-transmitted mutations than babies conceived without assistance.
In a final step, the group studied oocytes obtained by hormonal stimulation and by natural cycle, to determine whether hormonal stimulation was harmful. Mitochondrial mutations do not necessarily appear to be caused by hormonal stimulation. “In particular, a combination of age-related factors in conjunction with hormonal stimulation may result in a higher risk of abnormal oocytes,” says Spits.
“The risk of mutations in the mitochondrial DNA of the oocyte increases with age. During a normal cycle, mechanisms exist to eliminate mutated oocytes and select only healthy cells. However, with hormonal stimulation for stimulate the production of oocytes, this mechanism is deactivated and the mutated oocytes are released.”
Spits’ team will conduct further studies, but this knowledge can be immediately implemented in assisted reproductive technology (ART) treatments to limit the risk of oocytes with mutagenic mitochondria.
“It seems that the higher the number of oocytes obtained after hormonal stimulation, the higher the risk of mutations. In the future, we can pay more attention to achieving a good balance of oocyte yield adequate and minimizing the risk of mutations,” Spits said. concludes.
More information:
Joke Mertens et al, Children born after assisted reproduction are more often carriers of a mitochondrial genotype associated with low birth weight, Natural communications(2024). DOI: 10.1038/s41467-024-45446-1
Provided by the Free University of Brussels
Quote: Research team discovers genetic cause of low birth weight in children conceived after fertility treatment (February 12, 2024) retrieved February 12, 2024 from
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