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Increased Risk of Hypertension due to IVF?

A new study has created a great deal of uncertainty among patients

Icon image | Photo: Shutterstock

A recently published study (see link) conducted by a Swiss working group on the increased risk of high blood pressure in children conceived by assisted reproductive technologies (ART) is currently making big waves, not least through nonstop media coverage. Additionally, this was fueled by some statements made by the senior author of this publication. He insists that IVF should be considered as a cardiovascular risk factor, similar to the risk from smoking (NZZ of 7 September 2018).

Thus, the study suggests a direct correlation between IVF treatments and specific health risks. This, of course, leads to much uncertainty among couples who either have already started treatment or who are still considering the use of assisted reproductive technologies. Against this background, it is even more important for us at the IVF Zentren Prof. Zech to provide a scientifically well-founded analysis of this study in order to enable our patients to make informed, fact-based decisions. To this end, we have published a response letter (more to follow) in the specialist magazine Journal of the American College of Cardiology where the study was published. In that respect, we would like to give a few words of explanation.

Small study population

The study in question is a so-called follow-up study including only 54 children conceived after ART procedures in just a single fertility clinic in Switzerland. Designed as case-control study, neither the patients in the study group nor those in the control group were randomized. Therefore, scientific evidence for this type of study is rated as low. A recently published meta-analysis (see link) does not support the causal link between ART (Assisted Reproductive Technologies) and cardiovascular alterations postulated by Meister et al. Brief explanation: A meta-analysis is, so to speak, the Rolls Royce amongst scientific studies. It analyses all previous research studies worldwide and identifies significant trends.

Absence of information on medical history, cause of infertility and assisted reproductive techniques used

Apart from the study design and the small study population, the study by Meister et al. revealed a series of additional shortcomings. The authors of the study failed to provide a detailed anamnesis of the patient’s parents with respect to their cardiovascular health and the underlying reason(s) for their infertility or the specification of the ART techniques applied. In order to make an objective assessment, such an approach would be of utmost importance, since the authors suggest that ART-induced epigenetic mechanisms are responsible for the cardiovascular alterations. In spite of the small study population and the “anamnestic gaps” described above, the authors postulate a causal correlation between changes in the health of the children tested and the use of assisted reproductive techniques.

Extrapolation of data observed earlier in an animal model

Already the first study conducted by the same working group in the same patient cohort (Scherrer et al., 2012) has been criticized (see link) for the extrapolation of findings obtained from animal studies to IVF in humans. The authors suggested possible epigenetic mechanisms to be responsible for the alterations and referred to one of their own studies performed on mice generated by ART. These mice exhibited increased levels of impaired imprinting and DNA promoter methylation of the eNOS gene (endothelial nitric oxide synthase – enzyme playing an important role in regulating blood pressure). However, the transferability of data from the animal to the human model, especially with regard to reproduction and embryogenesis is extremely limited!

There is something dubious about postulating a causal link

In view of these facts, it can be stated that the postulated correlation between reproductive medicine and cardiovascular alterations, extrapolating a general health problem in all ART-conceived children is not only questionable but also scientifically highly dubious. In addition, this approach gives rise to numerous questions such as, inter alia, the minimum quality requirements for scientific studies and the way the findings are communicated by the media, often degenerating into downright sensationalism.

Modus operandi of the media fuels up fear and anxiety

Today, it is current practice for numerous media to communicate alleged research findings in the form of news coverage. They often jump to premature conclusions and tend towards sensationalism. This is counterproductive and causes uncertainty and fear among people. It seems to be common practice to present a problem, as in this case, for example, the increased risk of hypertension due to ART, without providing sufficient information in order to be able to reconstruct the situation and produce a solution to the problem. Particularly in the field of ART, there are many factors that come into play, involving even genetic alterations inherited from the parents. Therefore, an assessment should always include the analysis of the infertile couple’s medical history (anamnesis), the nature of their infertility issues and the diagnosis and treatment methods used.

In closing, Dr. Maximilian Murtinger, medical director of NEXTCLINIC IVF Zentren Prof. Zech – Bregenz (AT), emphasized that the primary objective of any IVF treatment is to achieve a pregnancy and the birth of a healthy child:

M. Murtinger

“We attach great importance to the quality of our work and the safety of our patients. Our success depends largely on the trust and confidence of our patients. Our treatments are based on scientifically verified state-of-the-art medical procedures that are consistent with the existing legal requirements. Our main focus here is always on patient well-being and the safety and health of all persons involved.”


Links:
» Association of Assisted Reproductive Technologies With Arterial Hypertension During Adolescence

(Study | https://www.sciencedirect.com)

» Cardiovascular and metabolic profiles of offspring conceived by assisted reproductive technologies: a systematic review and meta-analysis

(Meta-analysis | https://www.ncbi.nlm.nih.gov)

» Letter by Andreassi Regarding Article

(Letter | https://www.ncbi.nlm.nih.gov)

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(Start page | https://www.fertility-treatment-blog.com)