Smoking exposure in pregnancy: Use of salivary cotinine in monitoring

The role of salivary cotinine for monitoring maternal pregnancy smoking as an alternative to self-reported smoking exposure is not well established. This was a case-control study to assess the correlation between maternal self-reported pregnancy smoking exposure and postnatal salivary cotinine levels in 90 mothers with a baby with fetal growth restriction (cases) and 180 mothers with a normal birthwieght for gestational age infant (controls) attending the Liverpool Women's Hospital for delivery between 2004 and 2005. Cases had increased exposure to cigarette smoke during pregnancy compared to controls. Using the salivary cotinine assay as the reference two-thirds of women, both cases and controls, correctly reported their smoking status during pregnancy. There are limitations with the accuracy of self-supported pregnancy smoking as an exposure indicator, especially in mothers delivering babies with intrauterine fetal growth restriction (IUGR) who are also those most likely to smoke. In view of this there is a need to consider using salivary cotinine measurements in antenatal settings in order to facilitate monitoring of smoking exposure in pregnancy and for evaluation of deterrent interventions