Hypotrophic newborns sometimes develop iron deficiency and neurological deficit. The objectives of the present study are : to describe the socio-demographic characteristics of mothers who have given birth to hypotrophs and to determine their erythrocyte profile as well as that of their newborns, to identify the maternal factors associated with neonatal hypoferrinemia. Methodology U do cross-sectional descriptive study with an analytical component, lasting 12 months was conducted in 10 health facilities in Lubumbashi in the DRC. Mothers who gave birth at term with hypotrophs without a history of hemorrhage or acute inflammatory disease during a single-fetal pregnancy were included in the study. The determination of maternal and fetal biochemical parameters were performed according to the methods recommended by the International Federation Clinic Chemical (IFCC) and by the International Council of Standardization in Heamotology (ICSH) using the Automat AU480 Beckman for ferritin and CRP and using the SYSMEX KX21N automatic device for the determination of erythrocyte parameters. The data were analyzed using SPSS.23 software. Results The majority of mothers are 18 35 (54.4%) ; multiparous (42.5%), of low socio-economic level (62.7%), having had malaria (66.7%), consuming Kaolin (71.6%) without taking dewormer (76%) nor iron supplementation (61.9%). They had anemia in 76.9% of cases (Hb˂11gr%) with low ferritinemia (˂20μg / l) in 52% of cases. Newborn small for gestational age had a normal hemoglobin (Hb≥13, 5 gr%) in 73.9% of cases and a low férritnémie (˂60μg / L) in 32.8% of cases. The maternal determinants of neonatal hypoferrtinemia are maternal malaria (OR .113.43 [9.42-1364.53]), the birth interval less than 12 months (OR48.18 [6.37-364.57] ), not taking dewormers (OR : 16.26 [2.04-129.50]) or iron supplementation during pregnancy (OR7.03 [1.55- 31.90]). Conclusion The present study shows that hypotrophic newborns do not always have iron deficiency anemia. Iron supplementation should not be systematic in these newborns at birth but it will require an iron assessment (hemoglobin and serum ferritin) beforehand

Keywords : Low Birth Weight, Maternal Determinants, Neonatal Hypoferritinemia, Lubumbashi, DRC