Background and aims Nutrition is important for a harmonious development, especially to the low birth weight children. The purpose of this paper is to analyse the risk factors present in low birth weight children (Bw), by evaluating the status and the feeding practices in infants and establishing the factors which influence infant malnutrition.

Methods We have made a retrospective study of the malnutrition cases from the Department of Paediatrics Recovery of St Mary Clinical Hospital in Iasi, between 2013 and 2015. The lot included 74 infants of 2000–2500g, which presented malnutrition when hospitalised. The data were extracted from the observation files, complying with the ethical and deontological code of scientific research.

Results The study highlighted that the home environment as well as her social and economic level influenced the baby’s health, most of them coming from the countryside, 97.30% of the mothers of low social and economic level and 2.70% coming from the middle level.

There can be noticed from the study that 22.68% of the mothers were under 20, 24.32% of them were between 21 and 25 years old, 17.57% between 26 and 30, 20.27% between 31 and 35% and 12.16% over 35 years old.

As for the analysis of the civil status and the education level of the mother: 47.30% not married, 17.57% in a relationship, 35.14% married, 39% illiterate, 39% of elementary educational level and 22% of an average educational level. Out of these, 95% were housewives and 5% unemployed.

As for the nutrition given before the hospitalisation, 74.32 of the infants were wrongly fed, 17.57% mixed fed and 8.11% received inappropriate food.

The obtained results show that 40.54% of the infants presented a weight increase of less than 500g, 37.84% between 500–1000g, 10.81% between 1001–1500g, 6.76% between 1501–2000g and 4.05% more than 2000g.

The hospitalisation period lasted less than 15 days (7%), between 15 and 30 days (65%), between 31 and 60 days (21%) and more than 60 days (7%).

Conclusions Malnutrition is the most frequent malnutrition deficiency due to feeding errors and social and economic factors.

There has been noticed that more than half of the mothers are younger than 25, which is correlated to their lack of education; also, more than half were not married.

The social and economic level as well as the poor education of the mother influences the infant’s health. The proper nutrition regarding the quantities as well as the quality of the food led to weight recovery.