Introduction:
It is known that the quality and quantity of milk is directly related to the dietary habits of the mother. Despite that, the rates of maternal malnutrition during lactation are increasing in several countries; thus, observing its effects on the offspring is relevant. The present study aims to verify the effects of maternal malnutrition during breastfeeding on the skulls of adult-aged Wistar rats.

Material and methods:
Thirty-six newborn rats were divided in three groups: the control group, in which the mother received a regular commercial diet containing 23% protein in unlimited amounts; the protein-energy restriction group, in which the dam received a commercial diet containing 8% protein in unlimited amounts; the energy restricted group, in which the dam received a commercial diet containing 23% of protein in limited amounts. After weaning, all rats received the same diet as the control group until 180 days of age. Then, the rats were euthanized, and their crania were excised and measured in radiographic images. Afterwards, their skull was decalcified with nitric acid (5%) and histological samples were obtained and the thickness of the diploe was verified. Descriptive statistics and ANOVA followed by the Newman-Keuls test were performed for comparison purposes.

Results:
It was observed that the skull from the protein-energy restriction and energy-restriction groups was smaller and thinner than that of the control group in several parameters.

Conclusions:
Maternal malnutrition during the lactation period caused long-term effects in skull morphology of Wistar rats. These effects could not be reversed after regulation of the diet.