Dietary iron absorption in pregnancy - a longitudinal study with repeated measurements of non-haeme iron absorption from whole diet.

In 22 healthy women the non-haeme iron absorption (bone-marrow smears and haematological parameters) was studied at the 12th, the 24th and the 36th week of gestation and two months after delivery. In eight non-pregnant women and in seven pregnant women (at the 36th week of gestation) the absorption of food iron was measured from different types of meals. The iron absorption was measured from radioiron-labelled test meals using a whole-body counter with a very high sensitivity. During pregnancy the non-haeme iron absorption increased continuously from less than 1 % in early pregnancy to almost 15 % in late pregnancy. Calculations indicated that the amount of iron absorbed from the diet covered only about half of the demands. The increasing absorption of food iron during pregnancy seems to be related to the still more increasing demands. However, the very low absorption values in early pregnancy was quite unexpected. The amount of iron absorbed was actually below the basal demands, which means that even in early pregnancy, for reasons unknown, there is a negative iron balance. Further studies are necessary to elucidate the significance of this finding. Two months after delivery the absorption of iron from the diet was increased compared to in non-pregnant women and exceeded the demands at that phase thus indicating that a positive iron balance was achieved.