Currently in Spain, about 150,000 In Vitro Fertilization (IVF) treatments are carried out per year and about 34,000 Artificial Insemination (AI). With these figures, today, around 9% of Spanish babies are the result of Assisted Reproduction (AR) treatment.
However, there are many people who are respectful of using fertility aid methods. Many times they argue that it is not something natural, that the machine is being forced and that, perhaps, if they cannot have children it is because it has to be that way.
But… Is this true?
Is there any scientific evidence that shows that having children through assisted reproduction treatment carries any risk compared to having them by birth? natural form?
The truth is that the processes of in vitro fertilization They are often considered 'miracles' even for science itself. And, of course, they pose a challenge to the laws of nature. As such, it is also true that each face can have its tail.
Let's see what science says about it.
Studies on risks of assisted reproduction
Studies that analyze the potential consequences that children born through reproductive techniques could suffer are still not very concise. In many cases, the groups are few, the data are complex to compare, and there is a lack of studies with sufficient perspective to offer data related to the subsequent development of babies.
Almost all studies conducted focus on complications at birth: intrauterine growth restriction, birth complications, prematurity, low birth weight, small size for gestational age, increased malformations and higher perinatal mortality.
Complications at birth
However, a large French study analyzed 162 IVF singleton pregnancies with 263 pregnancies resulting from stimulated cycles (without IVF) and with 5096 natural pregnancies.
No significant differences were found between the first two groups with respect to complications. But the results do indicate that These complications are more common for pregnancies after ovarian stimulation (with or without IVF). compared to natural pregnancies.
For this reason, it is believed that the increased risk does not appear to be related to the IVF method itself, but rather to other factors common in these two populations. That is, the characteristics of the population, the underlying infertile state along with ovarian stimulation.
In the case of a higher prevalence of congenital malformations, it is believed that it is not due so much to the technique as to the characteristics of the parents who undergo them.
Mild cardiovascular disorders
Studies with a longer projection over time seem to confirm that the use of assisted reproduction techniques can lead to children with cardiovascular and metabolic alterations during adolescence or early adulthood.
In 2012, Swiss scientists, led by a team from Bern University Hospital, compared 64 children born with IVF techniques and 57 children conceived naturally and found that among the first group, the 30% of the participants showed high pulmonary arterial pressure, vascular aging premature birth, increased stiffness of blood vessels at high altitude, and an increased risk of hypertension in adolescence.
Other researchers have since concluded that assisted reproductive technology induces intrauterine cardiac remodeling that persists until the child is about 3 years old.
metabolic alterations
In the same study, researchers looked at 54 children conceived through IVF when they had a mean age of 16 years and compared them to 43 control participants with a mean age of 17 years.
Their blood levels of lipids and high-sensitivity C-reactive protein were normal and comparable, as were birth weight and gestational age.
In the study, maternal body mass index, maternal smoking, and overall maternal cardiovascular risk profile were also similar. However, the young people conceived through IVF seemed to be more susceptible to developing a metabolic pathology called insulin resistance.
According to the study's conclusions, it is also presumed that differences in cholesterol, glucose and other metabolic parameters could appear later in life.
The findings were published in the journal Circulation by professor of cardiology at the University of Sydney School of Medicine, David Celermajer.
However, he himself wanted to qualify and contextualize his findings.
"When all variables are considered, IVF parents should not worry. I think, to put it in perspective, IVF has given them, overall, very healthy children. And if this study is confirmed, it could imply that, once they grow up, they may have heart disease somewhat prematurely, in their 50s or 60s instead of 70s or 80s. So, if you compare that to the gift of life first, I don't think parents should be too worried right now.
The study was "relatively small," he said, and did not conclusively show that people born through IVF had more heart attacks or strokes.
"It just points to an area of potential concern rather than immediate concern."
Celermajer emphasized that the benefits outweigh the potential risks, but added that the recent research results provide a "somewhat worrying sign that manipulating nature in this way may have some adverse results."
Today, all the objectives in fertility research are focused on minimizing them.
Main causes of potential alterations in children born through assisted reproduction
During IVF, doctors remove an egg from the ovaries and then incubate it along with the sperm in the test tube. Alternatively, they may inject a sperm directly into the egg to help with fertilization. The embryo that this process creates is grown in a culture for a few days and then implanted into the mother's uterus.
This phase of development is incredibly critical.
In those first 10 days after the egg and sperm meet to form an embryo, so much happens to determine future health that even subtle changes in the physical and chemical environment can cause very important changes in the baby's development in the end. of gestation. Dr. Michael Miller, a cardiologist at the University of Maryland Medical Center, agrees that lThe reason for high blood pressure is likely due to how genes are expressed during the “stressful and unnatural” conditions that can occur with IVF.
There are two possible causes of cellular stress that embryos may experience.
One, the physical stress of being picked up, injected or handled, and the other, the chemical stress related to chemicals in the test tube environment or changes in the oxygen level.
Sometimes cells that grow in an environment where it is slightly more acidic, for example, can experience greater oxidative stress. And, in simple terms, this affects the cells' energy use, growth and development adversely.
Given this evidence that certain alterations could be a consequence of the chemical processes that occur while the embryo is still in the Petri dish, some scientists develop some fears.
It is believed that chemicals in crops could influence the expression of some genes and cause subsequent alterations. The fact that these alterations occur at such an initiatory moment in a being's life is especially worrying.
Being a stress experienced by the stem cells that we call pluripotent in the embryonic phase, it could end up affecting not only the blood vessels, but also other organs.
Little by little, studies on kidney, liver, lung, brain or other organ conditions that have not been studied in depth will grow.
However, members of the Swiss team also noted that many people who were not born through IVF have these same genetic markers in advance and does not represent a significant reduction in either their quantity or their quality of life.
Many studies have been done on the psychosocial development of children born through IVF and their likelihood of developing autism spectrum disorders, with or without hyperactivity. None of them have identified significant differences in this population group with respect to the general population.
Prevention and actions to avoid alterations in assisted reproduction
For now, studies say that assisted reproduction techniques represent a potential increase in the probability of suffering from cardiovascular and metabolic disorders in adolescence. Given this potential situation, increasing healthy lifestyle habits is, without a doubt, the first recommendation to make.
It is essential to maintain a diet mainly low in trans fats, from cooked vegetable oils, and low in poor quality saturated fats, such as meat from large animals that have not been able to move freely.
In addition, it is important that the diet is especially rich in vegetables, fruits, seeds, nuts, legumes and good quality protein, such as fish, shellfish, poultry, eggs or grass-fed meat.
Excess flour and sugar favors the appearance of metabolic syndromes that could end up negatively influencing cholesterol levels and cardiovascular pathologies. Quite the opposite of what would be recommended for the IVF Generation.
And studying the beneficial effects of intermittent fasting for this type of pathology would be equally recommended.
The last recommendation, but no less important, would be to maintain a high daily movement level. Minimum 30 minutes of gentle physical exercise a day, preferably outdoors and in the sun. If it were possible to combine gentle exercise with strength exercises, which help increase muscle mass, it would be even more interesting in order to avoid metabolic pathologies. Muscle is a large consumer of blood sugar. The more muscle, the less risk of diabetes.
References:
- François Olivennes, P. Rufat, B. André, A. Pourade, MC Quiros, René Frydman, Pregnancy: The increased risk of complication observed in singleton pregnancies resulting from in-vitro fertilization (IVF) does not seem to be related to the IVF method itself, Human Reproduction, Volume 8, Issue 8, August 1993, Pages 1297–1300, https://doi.org/10.1093/oxfordjournals.humrep.a138245
- Bengt Källén, Orvar Finnström, Karl Gösta Nygren and Petra Otterblad Olausson. In vitro fertilization (IVF) in Sweden: Risk for congenital malformations after different IVF methods. Clinical and Molecular Teratology. Birth Defects Research Part A. First published: January 27, 2005 https://doi.org/10.1002/bdra.20107
- Konstantinidis G., Pavlović V., Stojadinović A. and Katić K. Characteristics and morbidity of prematurely born newborns conceived with assisted reproductive technologies. Srpski arhiv za celokupno lekarstvo 2020 Volume 148, Issue 9-10, Pages: 571-576. https://doi.org/10.2298/SARH191029049K
- Paul Merlob, Onit Sapir, Jaqueline Sulkes, Benjamin Fisch. The prevalence of major congenital malformations during two periods of time, 1986–1994 and 1995–2002 in newborns conceived by assisted reproduction technology. European Journal of Medical Genetics, Volume 48, Issue 1, 2005, Pages 5-11, ISSN 1769-7212, https://doi.org/10.1016/j.ejmg.2005.01.019.
- Michael von Wolff and Thomas Haaf. In Vitro Fertilization Technology and Child Health. Risks, Mechanisms and Possible Consequences. Dtsch Arztebl Int. 2020 Jan; 117(3): 23–30. Published online 2020 Jan 17. doi: 10.3238/arztebl.2020.0023
- Verdult R. (2021) The Psychotherapeutic Treatment of IVF/ICSI Babies: A Clinical Report. In: Evertz K., Janus L., Linder R. (eds) Handbook of Prenatal and Perinatal Psychology. Springer, Cham. https://doi.org/10.1007/978-3-030-41716-1_15
- Diop, H., Cabral, H., Gopal, D. et al. Early Autism Spectrum Disorders in Children Born to Fertile, Subfertile, and ART-Treated Women. Matern Child Health J 23, 1489–1499 (2019). https://doi.org/10.1007/s10995-019-02770-z
- Manon Ceelen, Mirjam M. van Weissenbruch, Jan PW Vermeiden, Flora E. van Leeuwen, Henriette A. Delemarre-van de Waal, Cardiometabolic Differences in Children Born After in Vitro Fertilization: Follow-Up Study, The Journal of Clinical Endocrinology & Metabolism, Volume 93, Issue 5, 1 May 2008, Pages 1682–1688, https://doi.org/10.1210/jc.2007-2432
- Cui, L., Zhou, W., Xi, B. et al. Increased risk of metabolic dysfunction in children conceived by assisted reproductive technology. Diabetologia 63, 2150–2157 (2020). https://doi.org/10.1007/s00125-020-05241-1
- Christina Bergh & Ulla-Britt Wennerholm (2020) Long-term health of children conceived after assisted reproductive technology, Upsala Journal of Medical Sciences, 125:2, 152-157, DOI: 10.1080/03009734.2020.1729904
- Taravat Talebi, Neda Mohsen-Pour, Mahshid Hesami, Majid Maleki & Samira Kalayinia (2021) The association between in vitro fertilization and intracytoplasmic sperm injection treatment and the risk of congenital heart defects, The Journal of Maternal-Fetal & Neonatal Medicine, DOI: 10.1080/14767058.2021.1949705
- Derk Kuiper, Annemieke Hoek, Sacha la Bastide-van Gemert, Jorien Seggers, Douwe J Mulder, Maaike Haadsma, Maas Jan Heineman, Mijna Hadders-Algra, Cardiovascular health of 9-year-old IVF offspring: no association with ovarian hyperstimulation and the in vitro procedure, Human Reproduction, Volume 32, Issue 12, December 2017, Pages 2540–2548, https://doi.org/10.1093/humrep/dex323
- Frank van Balen Development of IVF Children, Developmental Review, Volume 18, Issue 1, 1998, Pages 30-46, ISSN 0273-2297, https://doi.org/10.1006/drev.1997.0446.
