Opium use during pregnancy and infant size at birth: a cohort study

Table 3 Risk ratios (RR) and 95% confidence intervals (CI) for the associations between opium and tobacco use during pregnancy and risk of short birth length at term birth

	Pregnancies	Short birth length ^a	Crude	Adjusted ^b
	N	N (%)	RR (95% CI)	RR (95% CI)
Opium
Unexposed	850	50 (5.9)	Reference
Exposed	798	92 (11.5)	1.95 (1.38–2.75)	2.01 (1.40–2.89)
Tobacco and opium
Unexposed	850	50 (5.9)	Reference
Exposed to opium only	616	70 (11.4)	1.93 (1.36–2.73)	2.00 (1.37–2.92)
Exposed to tobacco and opium	182	22 (12.2)	2.03 (1.26–3.27)	2.04 (1.20–3.48)

^aBirth length less than 47 cm (below the 5th percentile of birth length of unexposed and term live birth)
^bAdjusted for: maternal age, height, BMI, parity, weeks gestational age, infant sex, husband’s occupation, and residential place

ISSN: 1471-2393