The effect of the 1998 Master Settlement Agreement on prenatal smoking.

The Master Settlement Agreement (MSA) between the major tobacco companies and 46 states created an abrupt 20% increase in cigarette prices in November 1998. Earlier estimates of the elasticity of prenatal smoking implied that the price rise would reduce prenatal cigarette smoking by 7-20%. Using birth records on 9.8 million US births between January 1996 and February 2000, we examined the change in smoking during pregnancy and conditional smoking intensity in response to the MSA. Overall, adjusting for secular trends in smoking, prenatal smoking declined by less than half what was predicted in response to the MSA.