Although such technology has been used for about three decades, there is little data on the long-term health concerns of children born from these methods. Of course, the lack of data could be due to the fact that “clinically manifest disease may not yet have had time to develop,” Scherrer and colleagues said.
To determine whether these children exhibited any subclinical cardiovascular dysfunction, researchers recruited 65 healthy Swiss children (mean age 12) conceived by assisted reproductive technology. They also enrolled 57 control children born during the same period.
Among the children conceived using assisted reproductive technology, 21 were conceived by in vitro fertilization and 44 by intracytoplasmic sperm injection. Fresh embryos were transferred immediately in 48 cases; in the remaining 17, zygotes were kept frozen to be transferred later.
Researchers found many baseline similarities between the controls and the children conceived with reproductive assistance, including arterial blood pressure; body mass index; levels of lipids, glucose, and insulin; and birth weight, which has been theorized as a possible reason for vascular dysfunction later in life.
“It does indicate that you’re more likely to have high blood pressure, probably more likely to have diabetes and probably more likely in middle age to have a heart attack or stroke, and so the sensible precaution would be to take every healthy measure that’s open to you in regards to diet, exercise and regular check-ups with your GP.”
Also of concern, he said was the possibility that stress experienced by stem cells in the embryo might affect not only blood vessels but other organs as well. “So it is a bit of a clarion call to look at the kidney, liver, brain, lungs and other organs which could also be affected.”
Professor Celemajer described IVF as “a miracle” and stressed that the benefits outweighed the potential risks, but added that the growing body of research provided a “somewhat disturbing signal that manipulating nature in this way may have some adverse results.”
The two groups also had similar maternal characteristics such as gestational age, body mass index, smoking status, and cardiovascular risk profile.
Echocardiography revealed no structural heart damage in either group of children.
Along with the differences in brachial and carotid arterial function, the children conceived with reproductive assistance also had pulmonary vascular dysfunction. For example, children conceived with reproductive assistance had a 30% higher mean systolic pulmonary artery pressure (39 versus 30 mm Hg, P<0.0001).
To test pulmonary function, researchers used high-altitude exposure "because hypoxia induces exaggerated pulmonary hypertension in persons displaying endothelial dysfunction."
Arterial oxygen saturation and the cardiac index were similar in both groups.
Also similar were the mean diameter of the inferior vena cava and its respiratory change, and the left atrial pressure.
To the researchers, this signified that the higher systolic pressure in the children conceived with assisted reproductive technology was due to pulmonary vascular dysfunction and not cardiac dysfunction.
There were no systemic and pulmonary differences between children conceived with the help of in vitro fertilization and those born after intracytoplasmic sperm injection. Nor were there differences between children of mothers whose embryos were transferred immediately or those whose mothers had their embryos frozen for a later transfer.
Several other analyses were conducted, which included looking for arterial differences related to children born to sterile and fertile parents or related to children conceived naturally after hormonal stimulation of ovulation. Researchers said that none of these factors played a role in vascular dysfunction.
In fact, multivariate analysis pegged assisted reproductive technology as an independent predictor of all vascular parameters.
"Collectively, these observations provide no evidence that parent-related factors play an important role and suggest that vascular dysfunction in offspring of assisted reproductive technology is related to the procedure itself," researchers wrote.
Despite the small study sample, Celermajer said the study has several strengths, including the various analyses between children born with reproductive assistance and controls, as well as between the various techniques and between the sterile and fertile parents.
Funding was provided by the Swiss National Science Foundation, the Eagle Foundation, the Leenaards Foundation, the FABER Foundation, and the Placide Nicod Foundation.
Neither the authors of the study nor the editorialists had any conflicts of interest to report.
Primary source: Circulation
Source reference: Scherrer U, et al “Systemic and pulmonary vascular dysfunction in children conceived by assisted reproductive technology” Circulation 2012, 125: 1890-1896
Additional source: Circulation
Source reference: Celermajer DS, “Manipulating nature : Might there be a cardiovascular price to pay for the miracle of assisted conception?” Circulation 2012, 125: 1832-1834
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