For the purposes of this study, TLFB data and maternal oral fluids were used to ascertain maternal click here smoking status during pregnancy. Maternal oral fluid was collected at each prenatal interview to provide objective evidence of recent exposure. The oral fluid specimens were analyzed by a commercial laboratory for cotinine, the primary nicotine biomarker, with enzyme-linked immunosorbent assay (ELISA) for the first 42 women recruited into the study. Liquid chromatography�Ctandem mass spectrometry (LC�CMSMS) at 5 ng/ml cutoff was used thereafter. In addition to TLFB, maternal oral fluid was used to determine maternal smoking status and was not used for identification of SHS exposure. There were three women who had cotinine below the 5 ng/ml cutoff for active use.

All three of these women were in the smoking group due to self-reported cigarette use during pregnancy. Thus, maternal smoking status was determined by a combination of maternal report and maternal oral fluid results. Mothers were included in the smoking group if self-reports were positive, even if oral fluid results were negative (38% of women in the smoking group). Similarly, mothers who reported that they did not smoke but had positive oral fluid samples (1% of women in the smoking group) were included in the smoking group. Of the women in the smoking group, 76% had a positive oral fluid sample, 99% reported smoking, and 74% had both a positive oral fluid sample and positive self-report.

Social Network Smoking Potential sources of exposure in the women’s social environment consisted of the following: if women had a spouse or partner who lived in the household, if their partner had ever smoked cigarettes, if he was a current smoker, and if the partner smoked inside the home. Women were also asked if their partner smoked other forms of tobacco such as cigars or pipes, with the same follow-up questions. A dummy-coded partner smoking status was determined on the basis of these questions. Other questions regarding sources of SHS exposure consisted of the number of smokers in the household excluding the partner, number of relatives who smoked, and number of friends who smoked. SHS Exposure Frequency of SHS exposure in the past 7 days was the primary dependent measure in most analyses. Frequency of exposure is an important indicator of amount of exposure in pregnancy AV-951 that may be most critical for the fetus. Women were asked about the number of days in the past week that they were in the same room, in the same car, or outside with someone who was smoking. Responses to these three variables were averaged to create a composite measure of average frequency of SHS exposure (range 0�C7). This composite measure had high internal consistency, Cronbach’s alpha = 0.90.