Table 2.

Prevalence of low birthweight and neonatal intensive care unit (NICU) transfer/admission according to maternal smoking intensity exposure status

Maternal smoking intensity status	Low birthweight N = 80,431 (2.4%) % (95% CI)	NICU transfer/admission N = 148,172 (4.5%) % (95% CI)
Quitter-Low	3.6 (3.4, 3.8)	5.3 (5.0, 5.5)
Quitter-High	3.7 (3.4, 4.0)	5.8 (5.5, 6.2)
Maintainer-Low	5.4 (5.2, 5.6)	6.1 (5.9, 6.3)
Maintainer-High	6.7 (6.5, 6.9)	7.0 (6.8, 7.2)
Reducer	5.8 (5.6, 6.1)	6.3 (6.0, 6.6)
Increaser	4.9 (3.8, 5.9)	6.4 (5.1, 7.6)

CI confidence interval; Low intensity smoking: < 10 cigs/day; High intensity smoking: ≥10 cigs/day