IVF may lead to abnormal body fat distribution

NEW YORK (Reuters Health) - In vitro fertilization (IVF) may alter developmental pathways putting children conceived by this method at risk for elevated levels of body fat, study findings suggest.

Because prior research suggested that pre-conception and pre-implantation conditions may play a critical role in prenatal and postnatal development, Dr. Mirjam M. van Weissenbruch, VU University Medical Center, Amsterdam, and colleagues investigated the body composition of 466 children who were conceived by IVF or spontaneously.

The children, ranging between 8 and 18 years old, were all single births of women treated for fertility problems at Amsterdam's VU Medical Center, the researchers report in The Journal of Clinical Endocrinology and Metabolism.

The 233 children conceived by IFV had significantly lower birth weights and were born earlier than the 233 children spontaneously conceived. At ages ranging from 8 to 18 years, the IVF-conceived children had higher body fat mass, the researchers report.

Measurements of under-the-skin body fat at locations such as the upper arm and waist, showed significantly higher peripheral body fat among the IVF-conceived children than the spontaneously conceived children. Total peripheral skinfold measurements were 40.4 mm among IVF-conceived compared with 37.1 mm among spontaneously conceived children.

Conversely, the researchers found a significantly lower percentage of lean peripheral tissue among IVF-conceived children.

Body fat scans among the children who had reached puberty showed that children conceived by IVF had more peripheral fat, central fat, and total-body fat levels than spontaneously conceived children.

However, the investigators noted no differences in the children's skeletal status, as measured by bone mineral content and bone mineral density, outside of variations caused by age, height, and gender.

Because body fat is a major risk factor for heart disease, the researchers suggest these findings confirm the need for long-term monitoring of children born after IVF to identify and address potential health problems.

SOURCE: The Journal of Clinical Endocrinology and Metabolism, September 2007.