reproductive health

A scientific team has generated synthetic human embryos using stem cells, reports the British newspaper The Guardian. The authors, who announced the breakthrough at the annual meeting of the International Society for Stem Cell Research in Boston (USA), say the model embryos, similar to those found in the early stages of human development, could be crucial for research into genetic disorders and the causes of miscarriages, according to the newspaper. However, the work also raises ethical and legal issues.

A study published today in the NEJM examines the risk of relapse in breast cancer patients who decide to pause endocrine therapy to try to become pregnant. The results show that temporarily stopping treatment does not confer an increased risk in the long term, but the authors warn of the need for further follow-up.

Two decades of research has found no differences in psychological well-being and the quality of family relationships between children born through assisted reproduction with third-party intervention (gamete donation or surrogacy) and those born naturally. The results, published in Developmental Psychology, suggest that it is better to talk to them early, at preschool age, about their biological origins.

A sperm donor in the Netherlands has allegedly fathered more than 550 children in at least 13 clinics in the Netherlands and other countries. One of the mothers of these children and the Donorkind Foundation (Netherlands) have sued him. In Spain, there is a national registry of gamete and pre-embryo donors, and the law on assisted human reproduction techniques does not allow more than six babies to be born from the same donor. 

Researchers in the United States have tested a new technique to select sperm and thereby increase the chances that the embryo will be of either sex. The proven efficacy is around 80 %. Although some countries such as the United States allow this type of procedure, in Spain it is prohibited except in cases of prevention of diseases linked to sex chromosomes. The authors of the article state that sperm selection is more ethically acceptable than embryo selection. The results are published in the journal PLOS ONE.

A study carried out by researchers at the University of Amsterdam Medical Centres on more than 220,000 children examines the academic performance at age 12 of children born by induced labour. According to the authors, a reduction in scores was observed in infants born after induced labour between 37 and 41 weeks. The research is published in Acta Obstetricia et Gynecologica Scandinavica.

A study in mice found that a molecule called TDI-11861 works as an oral male contraceptive, temporarily blocking sperm function. The paper, published in Nature Communications, presents the research as a step towards an on-demand male contraceptive drug: the user could take a birth control pill before sex and become fertile again the next day. Four co-authors of the study have founded a company in the US to develop such products. 

A study published in the journal PLOS Medicine concludes that the development and academic outcomes of girls and boys conceived with in vitro fertilisation (IVF) are no different from those of children conceived naturally. The analysis is based on data from two national assessments in Australia, including more than 585,000 children born between 2005 and 2014 (more than 11,000 conceived by IVF). The first assessment measured the physical and emotional and cognitive health of children aged 4-6 years; the second focused on the numeracy and verbal skills of schoolchildren aged 7-9 years.

Results from a survey of more than 39,000 menstruating individuals reveal that 42% experienced heavier bleeding after SARS-CoV-2 vaccination. Among the most likely groups were pre-menopausal women, Hispanic or Latina women, those who had been pregnant, and those with conditions such as endometriosis and polycystic ovary syndrome.

Several results confirm that vaccination against covid-19 does not affect fertility. One of them, carried out on some 2,000 couples and published in the American Journal of Epidemiology, compares the ability to conceive naturally in vaccinated and unvaccinated couples. The other, in Obstetrics & Gynecology, studies some 1,300 vaccinated and unvaccinated women who have used different assisted reproductive techniques. Neither paper finds a link between vaccination and pregnancy.