Pregnancy increases considerably iron needs in mother and her foetus. The purpose of our study is to measure the effect of maternal anaemia on the foetus and the effect of iron supplementation on the maternal and foetal reserves. Therefore, we conducted a three-month cross sectional study at the gynaecological and obstetrics clinics of Aristide Le Dantec Hospital. Ninety-five women aged 16 to 43 years old and having an haemoglobin rate < 11 g/dl were recruited. Most of them were primipares. Among them 69 had a low ferritinemia (< 50 ng/ml), 36, a ferritinemia collapsed (< 30 ng/ml) and 13 virtually non-existent reserves (< 12 ng/ml). All newborns were born in terms with an apgar score >/= in 93 of them. Among them 24 had anemia (rate of haemoglobin < 14 g/dl) and 54.7% a low ferritinemia. There is no relationship between the maternal and foetal rates of haemoglobin; 74% of newborn had a normal rate of haemoglobin. Among 36 women with low ferritinemia only two gave birth to a newborn without iron reserves. In our study, among 68 women who received iron regularly, 41 had normal reserves and 43 gave birth to a newborn with high ferritinemia. There is significant difference between the women having received iron during their pregnancy and those not supplemented as regards the effect on newborn (p = 0.00001). The prevention of iron deficiency and anaemia can be done by the iron systematic and premat supplementation.