Pregnancy, and lactation are governed by hormones and neurophysiological processes, including differential expression of trophic factors, functional and structural synaptic plasticity and neurogenesis in different brain areas.Objectives:The aim of the study was to evaluate the amount of neurotrophic factors, synaptic plasticity and neurogenesis in the hippocampus of rats during pregnancy, lactation as well as in dams that were deprived from their pups one week after birth or treated with Finasteride or Clomiphene.Methods:Adult female Sprague Dawley CD rats were treated with finasteride (25 mg/kg, subcutaneously) or clomiphene (5 mg/kg, intragastrically) from day 12 to 18 of pregnancy. Dams during pregnancy, lactation and those deprived from their pups which were sacrified 7 days after delivery were used to study Brain Derived Neurotrophic Factor (BDNF) and Activity-Regulated Cytoskeletal (Arc) protein expression, dendritic spine density (DSD), and cell proliferation in the hippocampus.Results:BDNF, Arc and DSD markedly increased after 21 days of pregnancy (the time of delivery), an effect that lasted for 21 days during lactation and was abolished by physiological weaning (21 days after delivery). The modifications in the mentioned parameters were associated with a dramatic reduction of neurosteroid content when compared to estrus fe-males. In contrast, after 21 days of pregnancy we observed an increase in cell proliferation and a decrease during the first three weeks of postpartum. Finasteride and clomifene failed to modify the changes in BDNF and Arc content elicited by pregnancy and delivery. Pups deprivation induced a rapid reduction in the amount of BDNF, Arc and DSD while increasing cell proliferation.Conclusion:<jats:p/>In rats, the changes in plastic properties of hippocampal neurons during pregnancy, lactation and pups deprivation may play a crucial role in the modulation of maternal care.