What seemed to be a great problem could turn into a boon: couple that have children through in vitro fertilization (IVF) apparently have them ...bigger and healthier! Previously, it was known only that these children have a low risk of developing congenital abnormalities.

In the first long-term research monitoring the evolution of IVF children, researchers discovered that they may grow taller and present a healthier metabolism than other children in the similar age group have. The precise reason is not known, but it is supposed it could be due to subtle epigenetic alteration of imprinted genes or other genes that are formed during the IVF process.

"This study is one of the first of its kind and demonstrates that differences are present by mid-childhood in children born following IVF treatment," said lead author Dr. Harriet Miles, MD, of the University of Auckland in New Zealand.

The research team made its investigation on a sample of 69 healthy children aged 4 to 10 conceived using IVF and 71 naturally born control children. The scientists assessed their weight and body composition, bone age, insulin, lipid profile, and insulin-like growth factors. These results match studies made on animals, which point out that in vitro manipulation can induce persistent and possibly permanent metabolic changes.

Paradoxically, another research showed that pregnancy and live birth rates were significantly lower among women whose embryos were screened for genetic defects before being implanted in the womb, compared to patients whose embryos were not implanted by means of the same procedure: 25 % compared to 37 %. Over 60 % of the embryos implanted into the women who had them screened were abnormal. These findings point to the fact that genetic screening should not be done as a routine for women over 35 following an IVF treatment.

"Based on our research, I would say skip the pre-genetic screening and stick with regular in-vitro fertilization," said Dr. Sebastiaan Mastenbroek from the Center for Reproductive Medicine at the University of Amsterdam.

For pre-genetic screening, a single cell from a developing embryo is taken to be investigated for chromosomal defects, that can lead, for example, to Down's syndrome. And the risk for such conditions increases depending on the mother's age...