A new vaccine being developed by the National Institute for Drug Abuse to facilitate smoking cessation may also protect the fetus in utero from exposure to nicotine.  NicVax works by joining nicotine in the bloodstream to a protein to create a complex molecule that is too large to cross the blood-brain barrier.  This mechanism not only blocks nicotine penetration into the brain, but it also reduces the passage of nicotine across the placenta.  Smoking during pregnancy has many adverse effects on the development of the fetus, including increased rates of miscarriage, premature birth, low birth weight, increased rates of premature birth, early neonatal mortality, and sudden infant death syndrome. New research has also linked maternal smoking to neurobehavioral problems in children, such as attention deficit and hyperactivity.  The vaccine appears to be safe for use during pregnancy.  For more information, see the NIDA Web site at http://www.drugabuse.gov/about/welcome/Messagenicvax.html.  The source article is Nekhayeva, I.A., et al.  Effects of nicotine-specific antibodies, Nic311 and Nic-IgG, on the transfer of nicotine across the human placenta.  Biochemical Pharmacology 70(11):1664-1672, 2005.