A new study from Instituto Bernabeu relates genetic changes with chromosomal abnormalities in the embryo and the probability of ongoing pregnancy

The enzyme methylenetetrahydrofolate reductase (MTHFR) is involved in the metabolism of folic acid which is an essential nutrient for reproduction and pregnancy. There are studies that relate variants in the MTHFR gene with alterations in the embryo and problems with the pregnancy. The variants C677CT and A1298C are the most relevant. The aim of this study, accepted to be presented in a poster at this year's congress of the European Society of Reproduction ESHRE, was to study the relationship of these genetic changes with chromosomal abnormalities in the embryo and with the probability of pregnancy (ongoing pregnancy rate) after the transfer of chromosomally normal embryos.

To do this, variants C677CT and A1298C were analysed in 77 women who performed an IVF cycle with their own oocytes and also carried out a chromosomal analysis of the embryos (PGT-A) between June 2016 and December 2018. In addition, these changes in the MTHFR gene were studied in 407 embryos tested by PGT-A.

Different types of chromosomal abnormalities in the embryos were evaluated and no relationship was found between them and the presence of the variants in the MTHFR gene neither in patients nor the embryos. Also, the ongoing pregnancy rate upon the transfer of chromosomally normal embryos was compared between carrier and non-carrier embryos of these variants, and no differences were observed.

This study suggests that the C677CT and A1298C variants in the MTHFR gene do not affect the rate of chromosomal abnormalities in the embryos nor the ongoing pregnancy rate. 

Do maternal and embryo MTHFR gene polymorphisms have any influence on embryo chromosomal abnormalities and the ongoing pregnancy rate?

García-Hernández E., Morales R., Codina H., Cascales A., Lledó B., Ortiz JA., Ten J., Ll. Aparicio J., Bernabeu A., Bernabeu R.