Researchers from Belgium have found that a pregnant woman’s ability to metabolize fats is determined not only by her own genetic makeup but that of her infants as well.

Dr. Olivier S. Descamps from Universite Catholique de Louvain and colleagues report their discovery in the Journal of Lipid Research.

“The finding was surprising because it is not expected that the fetus could influence the lipid levels of the mothers,” Descamps told Reuters Health. On the other hand, “it makes sense” that the fetus “controls somehow the entry of food (in this case, cholesterol and fatty acids)” via the placenta.

Descamps and associates studied genes and proteins involved in fat metabolism from the blood and placenta of 525 pregnant women. Because all cells from the placenta originate from the fetus, they are a good marker of the genes and proteins produced by the baby.

The team looked at several genetic variations of two specific proteins important to lipid metabolism - lipoprotein lipase and apolipoprotein E.

They found that when these variants were present in the babies, their mother’s triglyceride and cholesterol levels were influenced to the same extent that they would be if the variants were present in the mothers.

But when both the mother and fetus had the same variants, the results could not always be predicted. For example, a genetic variant that raises the levels of triglycerides and cholesterol when expressed in mothers may lower these levels when expressed simultaneously by the fetus in the placenta.

“There may be potential implications of our findings” regarding women with severe inherited defects in lipid metabolism, Descamps said. These women are often advised not to have children due to a high risk for complications.

The new data hints that because their fetuses may be able to compensate for defects in lipid metabolism, the women may actually be able to bear children without complications.

SOURCE: Journal of Lipid Research, November 2005.