Table 1.

Comparison of self-reported smoking cessation during pregnancy with saliva cotinine cut-points of 10 ng/mL, including sensitivity analyses with cut-points of 3 and 15 ng/mL.

	Saliva cotinine
Self-report	≤10 ng/mL	>10 ng/mL	Total	p-value*
Spontaneous quitter	93.6, 90.5–96.6 (277)	6.4, 3.4–9.4, (19)	67.1, 59.4–74.8 (296)	0.0106
Later quitter	82.8, 76.5–89.0 (120)	17.2, 11.0–23.5 (25)	32.9, 25.2–40.6 (145)
Total	90.0, 87.2–92.9 (397)	10.0, 7.1–12.8 (44)	100.0 (441)
	≤3 ng/mL	>3 ng/mL
Spontaneous quitter	87.8, 84.2–91.5 (260)	12.2, 8.5–15.8 (36)	67.1, 59.4–74.8 (296)	0.0149
Later quitter	73.1, 63.8–82.4 (106)	26.9, 17.6–36.2 (39)	32.9, 25.2–40.6 (145)
Total	83.0, 79.3–86.7 (296)	17.0, 13.3–20.7 (75)	100.0 (441)
	≤15 ng/mL	>15 ng/mL
Spontaneous quitter	94.3, 91.2–97.4 (279)	5.7, 2.6–8.8 (17)	67.1, 59.4–74.8 (296)	0.0531
Later quitter	86.2, 79.4–93.0 (125)	13.8, 7.0–20.6 (20)	32.9, 25.2–40.6 (145)
Total	91.6, 88.7–94.6 (404)	8.4, 5.4–11.3 (37)	100.0 (441)

Values are expressed as %, 95% CI and (n).

^*Wald chi-square test for independence was used to assess differences in characteristics of women who were biochemically confirmed quitters and those who were not confirmed as quitters.