Assessment of Tobacco Exposure During Pregnancy by Meconium Analysis and Maternal Interview

Smoking during pregnancy can have serious obstetric and fetal complications. Therefore, it is essential to identify in utero exposure to tobacco, being meconium the matrix of choice for this purpose. Meconium (n = 565) was analyzed for nicotine, cotinine and hydroxycotinine by LC-MS-MS. Then, tobacco meconium results were compared with smoking habits during pregnancy and neonatal outcomes measures (birth weight, length, head circumference, gestational age and Apgar scores). Although meconium analysis increased identification of in-utero exposure to tobacco (17.7% meconium positive specimens vs 13.5% mothers admitting tobacco use during pregnancy), there was a statistically significant relationship between meconium results and interview answers (P < 0.001). Birth weight was significantly lower for newborns with meconium positive results in males (P = 0.023) and females (P = 0.001), while for length significance was only observed in females (P = 0.001); however, when excluding meconium specimens positive for other drugs, a statistically significant difference was only found for female weight (P = 0.045). Meconium analysis proved to be more reliable for tobacco prenatal exposure detection than maternal interview. In addition, positive meconium results increased the probability for low birth weight, especially in females.