An extensive investigation that has included all live births in Denmark (1994-2014), Finland (1990-2014), Norway (1984-2015) and Sweden (1987-2015), which added up to a total of 7,747,637 children , of which 171,735 were conceived through assisted reproductive techniques (ART), has revealed that the risk of being born with a serious heart defect is 36% higher in babies conceived through assisted reproduction. The findings have been published in the European Heart Journal.
Researchers analyzed whether children conceived through assisted reproductive techniques have a higher risk of developing congenital heart defects (CHD) compared to children conceived spontaneously. National data from TRA and birth records were cross-referenced with information from other health and population registries.
The outcomes considered were major congenital heart defects, severe CHD, 6 hierarchical groups of cardiac lesions and 10 major heart defects, diagnosed before birth or up to the first year of life (in Denmark, Finland and Sweden), and before birth or at born (in Norway). The relationship between TRA and DCC was evaluated using multivariable logistic regression analysis, adjusting for potential confounders.
Major congenital heart defects were detected in 3,159 children born after ART (1.84%) and in 86,824 children born after spontaneous conception (1.15%). The risk was higher in multiple pregnancies, regardless of the method of conception. Severe congenital heart defects were detected in 594 children born after ART (0.35%) and in 19,375 children born after spontaneous conception (0.26%). The risk was similar in both in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), as well as frozen and fresh embryo transfers.
Multiple pregnancy and risk of congenital heart defects
The authors of the work conclude that children conceived through assisted reproductive technology have a higher prevalence of major congenital heart defects which, although rare, can be serious conditions. However, the absolute risks are moderate and are, in part, related to multiple pregnancies, which are more common when assisted reproductive techniques are used.
“The main strength of this study is the large population, with data pooled nationally and cross-linked from several high-quality national registries. Furthermore, the relationship between different assisted reproduction techniques and congenital heart diseases has been explored and a very powerful statistical study has been used,” highlighted Rocío Núñez Calonge, biologist specializing in Human Reproduction and Scientific Director at UR International, in statements to SMC Spain. .
However, the specialist has also pointed out “important limitations.” “First of all, we must take into account confounding factors such as maternal age and male infertility, previously linked by other authors to the increased risk of heart disease at birth. Even, as the same authors have commented in the work, the relationship found between heart defects and pregestational diabetes. But the most important is that, although the risk of major congenital heart disease is higher in children born after assisted reproductive therapy, Sargisian et al. recognize that the absolute increase in risks appears to be modest and, therefore, , without clinical significance. In fact, the risk found in children after ART, of 1.84%, does not exceed that found in the general population, between 1 and 2%.”
“Future studies should focus on the internal problems of infertility rather than assisted reproductive techniques themselves to highlight any relationship between these factors and congenital heart disease.”
“Despite everything, this information must be transmitted to patients who receive counseling before assisted reproduction therapy. “This study also highlights the importance of transferring a single embryo to avoid the greater risks in multiple pregnancies,” adds Calonge, who concludes that “future studies should focus on the internal problems of infertility rather than on reproductive techniques.” assisted itself, in order to highlight in depth any plausible relationship between these factors and congenital heart diseases.
For her part, Yolanda Cabello, independent clinical embryologist and consultant in assisted reproduction, professor of the master’s degree in Health Management and Clinical Management at the International University of Valencia, has stated in statements to the same medium that “the study should not be so alarmist, since “There are no significant differences between children born after spontaneous pregnancies and those born after ART, and even more so knowing that we are already starting from people with an infertility problem and who do not achieve pregnancy naturally.”
Even so, he believes that “future parents should be informed of the risks of children born, just as we do in our country, but without scaring them. Perhaps the Nordic countries should offer more preimplantation genetic diagnosis techniques and perform greater genetic screening of patients before undergoing ART. It must be taken into account that the study has been carried out in countries with a low number of clinics, pregnancy data has been analyzed from 1984 to 2015 and there have been very significant changes in ART (improvement of conditions in the ART laboratories). IVF, culture media adapted to different situations, super-efficient cryopreservation techniques, improvement of embryonic selection thanks to algorithms created after morphokinetic studies, implementation of quality systems, etc.) and that in Spain and other countries the studies of malformations that are have not demonstrated higher rates of any malformation in children born with ART compared to those born with spontaneous pregnancies due to the gamete manipulation techniques themselves.”
