Low doses of nicotine-induced fetal cardiovascular responses, hypoxia, and brain cellular activation in ovine fetuses

Prenatal exposure to nicotine is associated with a variety of adverse outcomes. The present study investigated the effect of low doses of nicotine during pregnancy on fetal blood gases, cardiovascular system, and cellular activation in the brain. Intravenous administration of nicotine 10 or 25 μg/kg into ewe did not affect maternal blood gases, blood pressure, and heart rate. Maternal administration of nicotine also had no effect on fetal blood electrolyte concentrations, osmolality levels, and lactic acid levels. However, it significantly reduced fetal blood pO₂ levels and oxygen saturation, increased fetal arterial blood pressure and decreased heart rate in utero. In addition, exposure to low doses of nicotine increased the expression of Fos in the paraventricular nucleus (PVN) and subfornic organ (SFO) in the fetal brain. The data demonstrated that even low doses of nicotine could impact significantly on fetal cardiovascular and central nervous systems, as well as oxygen status, and suggested a toxic risk to fetuses of exposure to low levels nicotine or second-hand smoking during pregnancy.