The implications of trans fatty acids for pregnant women

The aim of this study conducted in France from 1996 to 1999 was to estimate TFAs consumption of mothers and placental transfert of TFAs as well as their consequences in the fetus. Previous studies suggest that dietary TFAs intake in mothers inhibited the metabolism of linoleic acid (18:2 9cis 12cis), increased requirement for essential fatty acid and influenced fetus growth of head circumference and weight. The population was 90 healthy pregnant women with newborn infants born at term, by elective caesarian section. We compared the level of TFAs in blood and maternal adipose tissues, obtained during the section after informed consent, and umbilical blood and isolated segment of whole umbilical venous and arterial in the newborn. TFAs isomers in maternal adipose tissue (AT), Total lipids (TL) (n = 31), Cholesterol esters (CE) (n = 29), red blood cells and cords vessels (n = 10), were determined by capillary gaz Chromatography (CP Sil 88 - 50 m x 0.25 mm). Results confirm that the Placental transfert of TFAs is similar (0.60%) in maternal total lipids and cord blood. However there is a selective transfert of 18:9trans 12cis (18:2tc) which is significantly higher in fetus and a competition between 18:2tc and 18:2 9cis 12cis) (R = -0.69, p < 0.001) in CE, but not interference with arachidonic acid. TFAs are present in fetal umbilical tissues (0.3% in umbilical vessels) and we noted that 18:2tc is not accumulated in tissues, so it is metabolized by fetus, but there is a positive correlation (R = +0.824, p < 0.005) in artery between Sigma 18:2t and 20:3n-9, a classical marker of EFA deficiency. There was no correlation between Sigma TFAs, 18:1 trans of maternal adipose tissue reflecting maternal consumption and head circumference or birthweight. These results could be linked to a lower TFAs consumption in France (2.7 g/day). TFA consumption remains a potential risk since it can interfere with linoleic metabolism and eicosanoid production, however our study showed that we have reached a level of TFAs consumption which does not interfere with fetal arachidonic metabolism and growth.