The Effects of Smoking on the Developing Fetus Essay -- Health Medical

The Effects of Smoking on the Developing Fetus The exposure of the fetus to nicotine during development has several effects. The most well known result of smoking is low birth weight of the infant. There are also some studies that reveal nicotine as a drug that can affect the brain of the developing fetus. Nicotine also has direct effects on the neurotransmitter systems in the CNS and may cause a decrease in cell growth which could result in mental impairment. The correlation between maternal smoking and low birth weight has been strongly established. Nicotine affects the placental function by inducing the release of norepinephrine and epinephrine into the maternal blood, which causes decreased blood flow to the placenta (1). The decreased blood flow causes a decrease in delivery of oxygen and nutrients to the fetus. This may have an effect on cell growth and development. High levels of carboxyhemoglobin are present in the blood of the mother and the fetus. This may decrease the capacity of the blood to transport oxygen and fetal hypoxia is the result (2). Fetal hypoxia and ischemia are major contributors to developmental defects, but nicotine has been implicated, in various studies, to have a direct affect on fetal development (3). Several studies suggest that nicotine interferes with cell acquisition and development in various brain regions. The developing nervous system seems to be more vulnerable to nicotine exposure than the rest of the body (4). This is important since nicotine readily crosses the placental barrier and fetal blood concentrations are equal to or above that of the mother (1). DNA can be used as a index for measuring cell acquisition. An experiment on rats by Lichtensteiger et. al. reported that DN... ...r. (1988) Prenatal adverse effects of nicotine on the developing brain. Progress in Brain Research. 73:137-157. 2. Moore, K. L. The Developing Human: Clinically oriented embryology, 4th edition. Philadelphia PA: W.B. Saunders Co., 1988, p.146. 3.Navarro, H. A., F. J. Seidler, J. P. Eylers, F. E. Baker, S. S. Dobbins, S. E. Lappi, T. A. Slotkin. (1989) Effects of Prenatal Nicotine Exposure on Development of Central and Peripheral Cholinergic Neurotransmitter Systems. Evidence for Cholinergic Trophic Influences in Developing Brain. The Journal of Pharmacology and Experimental Therapeutics, 251(3):894-900. 4. Navarro, H. A., F. J. Seidler, R. D. Schwartz, F. E. Baker, S. S. Dobbins, T. A. Slotkin. (1989) Prenatal Exposure to Nicotine Impairs Nervous System Development at a Dose Which Does Not Affect Viability or Growth. Brain Research Bulletin. 23:187-192.