A CANADIAN TERTIARY CARE CENTER STUDY OF MATERNAL AND UMBILICAL-CORD COTININE LEVELS AS MARKERS OF SMOKING DURING PREGNANCY - RELATIONSHIP TO NEONATAL EFFECTS

This study describes the prevalence of smoking among 3,220 pregnant wo men. Maternal and umbilical cord cotinine levels were compared with th e women's self-reported cigarette consumption, infant birth weight and antepartum and perinatal complications. Of the women who reported the mselves as bring active smokers (23%), 76% had a partner who smoked, a nd 38% reported exposure to environmental smoke in the workplace. Only 15% of nonsmokers had a partner who smoked, and 13% reported workplac e exposure. The mean number of cigarettes/day was 20.5 (35% CI 13.6-21 .4). The relative risk of having a small-for-gestational-age infant wa s significantly higher in smokers for mothers of both preterm (34-36 w ks, RR= 3.38, 95% CI 1.25 - 3.16) and term babies (greater than or equ al to 37 wks, RR= 2.04, 95% CI 1.58 - 2.63). Mean infant birth weight was 207 g lighter in the infants of smokers (p<0.001) and was inversel y correlated to maternal serum cotinine level. Birth weight dropped by 0.99 g for every 1 ug/L increase in cotinine (r=-0.13, p<0.01).