Indicated and non-indicated antibiotic administration during pregnancy and its effect on pregnancy outcomes: Role of inflammation

•Sterile inflammation is an important etiology of preterm labor.•Some antibiotics could induce pro-inflammatory cytokines in the absence of bacterial infection.•Consumption of some antibiotics in a non-infectious state may cause preterm labor. The objective of this study was to compare the release of endotoxin and pro-inflammatory cytokines as well as pregnancy outcomes after antibiotic exposure in healthy and bacterial infected pregnant rats. Thirty female Wistar pregnant rats were divided into five groups. Group A considered as control and received intraperitoneal saline 0.9% on 17th day of gestation or DG) and groups B and C treated with 20 mg/kg/day intravenous ceftriaxone and ceftazidime, respectively (DG: 18–20). Groups D and E received intraperitoneal E. coli and LPS on 17th DG respectively. Also, groups F and G received the same treatment as group D but they treated with the exact antibiotics mentioned for groups B and C (same dose and duration). Pregnancy outcomes as well as maternal sera levels of endotoxin, tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-6 were assessed using enzyme-linked immunosorbent assay. It was shown that group B had a higher IL-1β (P = 0.003) and TNF-α (P = 0.003) levels compared to the controls (CTC). Group C expressed a lower gestational duration (P = 0.007) as well as higher IL-6 (P = 0.025) and TNF-α (P