Reacción a "Babies born through assisted reproduction have increased risk of serious heart defects, study finds"

The study addresses an important problem, both because of the wide use of assisted reproduction techniques and because congenital heart disease is one of the most frequent congenital defects. It is a large, mutivariate study, methodologically correct, in which multiple comparisons have been made with the necessary adjustments and considering possible statistical confounding factors. The authors have acknowledged limitations that they have taken into account in the discussion of their results and in drawing conclusions.

The importance of this work lies in the fact that it provides evidence that can help, on the one hand, to inform couples who resort to assisted reproductive techniques to achieve a pregnancy, since, in this way, the information will be based on objective data and, considering that the magnitude of the risk identified is quite discrete, it can be reported without unnecessarily alarming. On the other hand, the results reinforce the recommendation to transfer a single embryo in order to avoid multiple gestations, which are also known to carry an increased risk for birth defects. Furthermore, the data provided can be taken into account in prenatal diagnostic studies during gestational follow-up.

Is the study of good quality? Yes, the sample size is large, covering several countries over a long period, multivariate logistic regression analysis has been performed, with different comparison groups, and a number of variables relevant to the relationship studied have been taken into account in the adjustments as possible statistical confounders. On the other hand, in the discussion, limitations have been acknowledged which, without doubt, have to be taken into account in the interpretation of the results, as the authors have done’.

Are the absolute risks statistically significant? Yes, although in this case the adjusted risks are more interesting than the absolute risks, and the adjusted risks are also statistically significant, although the magnitude of the risk obtained is not very high.

What would you highlight from the research? It is an interesting study that adds evidence about the increased risk of major, severe congenital heart defects resulting from the use of assisted reproductive techniques. Given the relatively frequent use of assisted reproductive technologies, it is important that couples are informed about this and other known risks. Since the magnitude of the increase in risk that has been identified is quite discreet, this is a fact that should be emphasised when informing these couples to avoid unfounded alarm. On the other hand, given that the risks identified have been associated in part with multiple gestations, this finding reinforces the now widespread recommendation to perform single embryo transfers, as opposed to the more common practice in the past when multiple embryo transfers were routinely performed. The data obtained are also important for prenatal diagnosis, which can be directed in these pregnancies to specifically rule out congenital heart defects, although as these are among the most frequent prenatal developmental defects, they are already routinely screened for.

Are there any notable limitations? The inability to include data on stillbirths and terminations after prenatal detection of fetal anomalies has been recognised by the authors as a limitation of the study. This fact may lead to an underestimation of the risk for this type of congenital defects, since, being severe structural defects, they are usually well identified prenatally, which results in a higher number of terminations of pregnancy for this reason (which could not be taken into account) and, therefore, a lower number of affected newborns, this being the sample analysed.