News

Study sparks health fears for IVF children



19 April 2012

The first IVF birth worldwide was in 1978, and so the oldest IVF children are now adults. Will they have the same health outcomes as those conceived "naturally"?

IVF (In Vitro Fertilisation) has brought the miracle of childbirth to hundreds of thousands; indeed it is now estimated that one percent to three percent of all births in developed nations involve IVF.

There have already been some health problems documented in IVF offspring. There is an approximately 20 percent to 30 percent increase in the risk of major malformations in IVF babies. However, the absolute risks of such outcomes is low.

Of greater concern would be any significant increase in the risk of the common cardiovascular diseases, such as heart attack or stroke.

A recent scientific study from Switzerland has found significant abnormalities in the blood vessels in the body and lungs of 12-year-old children who were born through IVF (published in Circulation this month). The investigators assessed 65 IVF and 50 non-IVF children, and found significant adverse changes in their developing blood vessels.

The study included the careful examination of relevant control groups. By doing this, the authors found that the problems observed were likely caused by events that influenced the embryo when "in the test tube". Other research has recently also found elevated blood pressure and blood sugar levels in IVF offspring.

Can environmental exposures so early in life actually alter the risk of later heart disease?

In 1992, we conducted research that found that abnormalities could be seen in the blood vessels of high-risk children. In 2005, we found increased blood vessel thickening in newborns with low birth weight, showing that even foetal events could potentially influence cardiovascular health in later life. It now seems that even the environment of the embryo might also influence heart-disease risk in adulthood.

What happens during IVF? A typical IVF cycle starts with the mother receiving hormone stimulation, followed by egg pick-up from the ovaries. Gametes (the egg and sperm) are then co-incubated "in the test tube" or a sperm may be injected directly into the egg, to aid fertilisation.

The resulting embryo is then grown in a culture medium for a few days before implantation into the mother's womb (either then or after a period of freezing).

The "test tube" parts of these events occur during a critical developmental period for the new embryo. This may be one reason why only 15 percent to 30 percent of IVF treatment cycles result in a successful pregnancy and delivery, because of a degree of "cellular stress" during the IVF process.

One potentially worrisome aspect of the recent Swiss research is the implication that cellular and/or gene changes are occurring in the embryo - a cluster of "stem" cells that are destined to form all the organs of the body.

If there are "test tube environment"-related changes sufficient to alter the development of healthy blood vessels in IVF children, might this mean other organ systems might also be affected in later life? This is an important topic for future research.

Do children born from IVF need to be treated differently, from a health point of view? It is very important for IVF parents and children not to be unduly alarmed by these preliminary findings, mainly based on a single study of only 65 children. It would seem prudent for IVF children to lead a "heart-healthy" lifestyle of no smoking, sensible diet, regular exercise and occasional check-ups by their GPs.

IVF has brought untold joy to many. With social changes mandating greater choices for family planning at older parental ages, the demand for IVF will likely continue to rise.

Recent studies now underscore the need for us to understand the possible adverse late outcomes of IVF and to focus on finding possible improvements that might prevent any potentially harmful late health consequences for these "miracle babies".

David Celermajer is the Scandrett professor of cardiology at Sydney Medical School at the University of Sydney.


Follow University of Sydney Media on Twitter

Media enquiries: Sarah Stock, 02 9114 0748, 0419 278 715, sarah.stock@sydney.edu.au