Maternal hair testing to disclose self-misreporting in drinking and smoking behavior during pregnancy

This study aimed to objectively verify smoking and drinking behavior during pregnancy and to disclose self-misreporting through maternal hair analysis. A total of 153 women attending a university hospital in Barcelona (Spain) were selected and interviewed after delivery, on their smoking and drinking habits during pregnancy. A 9-cm hair strand was collected and analyzed by liquid chromatography tandem mass spectrometry for the presence of nicotine (NIC) and ethyl glucuronide (EtG) as biomarkers of tobacco and alcohol consumption, respectively. Concentrations of EtG <7 pg/mg hair and ≥30 pg/mg hair in the 0–3-cm hair segment have been used to assess, respectively, total abstinence and chronic excessive consumption in the previous 3 months, with repetitive moderate drinking lying in the interval 7–30 pg EtG per mg hair. Hair NIC less than 1 ng/mg hair indicates non-exposure to tobacco smoke while hair NIC indicates daily active smoking. In the interview, 28.1% of women declared to have smoked occasionally during gestation, while only 2.6% stated to have consumed alcohol on more than one occasion during pregnancy. Hair testing of smoking biomarkers disclosed that 7.2% of women remained active smokers during the whole pregnancy (hair NIC: 3.21–56.98 ng/mg hair), 16.3% were passive non-smokers or occasional smokers (hair NIC: 1.04–2.99 ng/mg hair), while 76.5% were not exposed to any cigarette smoke (hair NIC < limit of quantification – 0.91 ng/mg hair). Conversely, alcohol hair biomarkers showed that only 35.3% of women were totally abstinent during gestation (hair EtG: 3.89–6.73 pg/mg hair), while 62.7% drank a non-negligible amount of alcohol during pregnancy (hair EtG: 7.06–26.57 pg/mg hair), and 2% were chronic excessive drinkers (hair EtG: 35.33–47.52 pg/mg hair). Maternal hair analysis has shown to be significantly more sensitive than interviews in revealing an alarming misreported prevalence of alcohol use during pregnancy. These findings stress the need to use objective measures to assess alcohol exposure and to consider the inclusion of targeted actions to reduce alcohol consumption in maternal-child health policies.