Relationship between moderate food restriction during pregnancy and Fe, Zn and Cu contents in maternal tissues and foetuses.

This study was undertaken to monitor Fe, Zn and Cu contents in several maternal tissues and the products of conception of rats submitted to moderate food restriction during pregnancy. Two groups of female rats, nonpregnant (NP) and pregnant (P1), were fed ad libitum. A second group of pregnant rats (restricted diet, P2) was fed for 14 days with the same intake as NP, then the intake was increased by 5% from day 14 to day 21. A significant decrease in liver Fe content was noted in P1 and P2 pregnant rats on day 21, being more marked in livers of P2. Increases in Cu and Zn contents in liver were induced during pregnancy, but the values were significantly lower in P2 than in P1. On day 21, no significant differences due to food restriction were noted in serum concentrations of these trace elements, placental weight and placental Fe. However, dam body weight gain, placental Zn and Cu contents were reduced in P2. Foetuses of undernourished dams exhibited at term lower weight and smaller amounts of Fe, Zn and Cu than those in P1. These results confirm that moderate food restriction during pregnancy produces intrauterine growth retardation and that newborns have low trace element contents (particularly in Cu), which make them dependent on correct postnatal supply.