Recurrent pregnancy loss affects approximately 5% of pregnant women worldwide and it is estimated that about half of the cases remain unexplained.

Diane Vaz's PhD study and thesis aims to contribute to a better understanding, diagnosis and guidance of women suffering from recurrent miscarriages, in a "funneling" work that seeks to provide answers for "a condition that is extremely impactful for women and couples".

Gestational loss or recurrent miscarriage - the scientific term - is characterized by the loss of two or more consecutive pregnancies up to 24 weeks of gestation.

"It is very different to tell a woman that she has this condition, that we do not know why, or to say that she has this condition, but we know the cause and we can study it and understand it better", she argued.

This study, the FMUP researcher explained to Lusa, is a contribution to making it possible, from a clinical and genetic counseling point of view, to redirect these women, who are not given a cause for the pregnancy loss.

To proceed with this research, the FMUP team is recruiting healthy women of reproductive age, with no history of recurrent miscarriages and with at least one child, who will constitute "the control group" and serve as a basis for comparison with the group diagnosed with recurrent miscarriages.

The volunteers, she explains, will not be subjected to any invasive tests, such as an endometrial biopsy. Only the collection of menstrual fluid samples is requested.

These samples, which will be obtained through a menstrual cup provided free of charge, will compare endometrial epithelial cells from healthy women with those from women who have suffered recurrent pregnancy losses, the latter recruited through collaboration with the Obstetrics service of the São João University Hospital Center (CHUSJ).

To ensure solid results, the researcher estimates that at least 15 to 20 women are needed for each group.

The FMUP team led by Sofia Dória, the project's principal investigator, will focus its research essentially on two families of endogenous retroviruses.

"Endogenous retroviruses result from ancestral insertions in our genome, that is, one is present in our genetic material and is normal. It is something explained by the evolutionary process, it is not the result of any infection", explained Diane Vaz.

Preliminary studies have shown that, compared to healthy women, these retroviruses have a lower expression in the endometrium in women with recurrent pregnancy losses, which indicates that these retrovirus families "must have vital functions in the endometrium, must be compromised and must, in turn, cause these losses", concludes the researcher.

The role of retroviruses in worsening diseases such as covid-19 has already been proven. A study by the Technological Development Center in Health (CDTS/Fiocruz), released in 2021, concluded that the presence of the endogenous human retrovirus of the K family (HERV-K) is associated not only with the most severe cases of covid-19, but also with early mortality from the disease.

The discovery has paved the way for new treatments for patients who are most severely affected by the infection.

HERV-K is an ancestral virus that infected the human genome when humans and chimpanzees began to diverge on the evolutionary scale.

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