Table 4

Plasma cotinine levels in paired maternal and newborn blood samples

Ranks for mother/newborn pairsaPa
Mean ± SD/108 nucleotidesNegative ranksbPositive rankscTiesd
MaternalNewbornNo.eSumfNo.eSumfNo.e
A. Plasma cotinine levels in all of the mother/newborn pairs (total sample)
Total cohort (n = 158)8.3 ± 24.514.2 ± 35.51334464265981P < 0.001
Nonsmoker (n = 104)3.2 ± 16.54.0 ± 18.3112013379060P = 0.001
Ex-smoker (n = 38)11.4 ± 28.217.7 ± 38.32211615020P = 0.005
Current smoker (n = 16)34.7 ± 38.672.2 ± 53.800151201P = 0.001
B. Plasma cotinine levels in mother/newborn pairs with blood drawn concurrently (concurrent samples)
Total cohort (n = 80)7.2 ± 25.97.7 ± 27.381593370339P < 0.001
Nonsmoker (n = 60)3.3 ± 19.43.4 ± 18.971042336230P = 0.008
Ex-smoker (n = 16)9.4 ± 22.910.1 ± 23.9177298P = 0.12
Current smoker (n = 4)57.0 ± 62.863.7 ± 71.400361P = 0.11
  • a Wilcoxon signed-ranks test.

  • b Newborn cotinine levels < maternal cotinine levels.

  • c Newborn cotinine levels > maternal cotinine levels.

  • d Newborn cotinine levels = maternal cotinine levels.

  • e Number of mother/newborn pairs.

  • f Sum of ranks.