Table 5– Odds ratios for neonatal outcomes, according to maternal asthma and cigarette smoking status during pregnancy, using nonasthmatic nonsmokers as the reference population

	Nonasthmatic smokers		Asthmatic nonsmokers		Asthmatic smokers		p-value for interaction
	OR	Adjusted OR (95% CI)	OR	Adjusted OR (95% CI)	OR	Adjusted OR (95% CI)	OR	Adjusted OR
Very preterm birth^#	1.83	1.69^¶ (1.51–1.89)	1.00	1.02^¶ (0.80–1.29)	2.27	1.96^¶ (1.52–2.52)	0.16	0.17
Preterm birth⁺	1.70	1.71^¶ (1.62–1.81)	1.14	1.15^¶ (1.02–1.29)	2.38	2.30^¶ (2.03–2.63)	0.007	0.007
IUGR^§	2.97	3.39^ƒ (3.17–3.63)	0.94	1.01^ƒ (0.85–1.21)	3.22	3.64^ƒ (3.12–4.24)	0.13	0.28
SGA^##	2.64	2.94^ƒ (2.81–3.07)	1.04	1.11^ƒ (1.01–1.23)	2.71	2.95^ƒ (2.65–3.28)	0.80	0.31
Neonatal intensive care admission	1.50	1.43^¶¶ (1.31–1.57)	1.20	1.07^¶¶ (0.91–1.26)	1.88	1.62^¶¶ (1.31–2.01)	0.76	0.70
Resuscitation required	1.21	1.15^¶¶ (1.03–1.28)	1.01	0.99^¶¶ (0.81–1.20)	1.05	0.91^¶¶ (0.66–1.27)	0.41	0.81
Oxygen therapy⁺⁺	1.26	1.24^¶¶ (1.17–1.32)	1.17	1.05^¶¶ (0.95–1.17)	1.67	1.56^¶¶ (1.35–1.80)	0.18	0.059
Stillbirth^#	1.52	1.49^¶ (1.24–1.80)	0.86	0.76^¶ (0.49–1.18)	1.43	1.13^¶ (0.67–1.90)	0.74	0.77
Neonatal death^§§	1.18	1.03^ƒƒ (0.78–1.37)	0.90	0.91^ƒƒ (0.55–1.52)	1.33	1.15^ƒƒ (0.57–2.35)	0.62	0.66
Congenital abnormalities	1.07	1.03^¶ (0.94–1.13)	1.23	1.21^¶ (1.06–1.39)	1.32	1.26^¶ (1.01–1.57)	0.99	0.96

IUGR: intrauterine growth restriction; SGA: small for gestational age. ^#: ≤32 weeks; ^¶: odds ratios adjusted for maternal age, parity, ethnicity, Socio-Economic Indexes for Areas (SEIFA), year of birth, pre-existing hypertension, pre-existing diabetes; ⁺: <37 weeks; ^§: below the third centile; ^ƒ: odds ratios adjusted for maternal age, SEIFA, year of birth, pre-existing hypertension, pre-existing diabetes; ^##: below the 10th centile; ^¶¶: odds ratios adjusted for maternal age, parity, ethnicity, SEIFA, year of birth, pre-existing hypertension, pre-existing diabetes, method of delivery, hypertensive disorders of pregnancy; ⁺⁺: >4 h; ^§§: <28 days; ^ƒƒ: odds ratios adjusted for maternal age, parity, ethnicity, SEIFA, year of birth, pre-existing hypertension, pre-existing diabetes, hypertensive disorders of pregnancy. Figures in bold indicate significant adjusted OR at p<0.05.