Adverse effects of parental smoking during pregnancy in urban and rural areas

Table 5 Parental smoking during pregnancy correlated with gestational age (weeks) and preterm birth, stratified by residence

	Urban				Rural
	Gestational age	p	Preterm birth	p	Gestational age	p	Preterm Birth	p
	Mean ± SE	p	OR (95% CI)	p	Mean ± SE	p	OR [95% CI]	p
Parental smoking during pregnancy^a
Neither parent	39.69 ± 0.1	-	1.00	0-	39.84 ± 0.1	-	1.00	-
Only father	39.54 ± 0.1	0.219	1.16 (0.69-1.95)	0.582	39.91 ± 0.1	0.482	1.13 (0.61-2.08)	0.704
Only mother	39.07 ± 0.4	0.086	1.87 (0.56-6.18)	0.307	38.53 ± 0.3	<0.001	5.14 (1.72-15.41)	0.003
Both parents	38.60 ± 0.4	0.003	4.70 (1.74-12.73)	0.002	39.64 ± 0.2	0.440	1.49 (0.28-7.82)	0.638
Paternal smoking amount^b
None	39.61 ± 0.1	-	1.00	-	39.66 ± 0.1	-	1.00	-
1-10 cigarettes/day	39.73 ± 0.1	0.339	0.76 (0.46-1.26)	0.286	40.10 ± 0.1	<0.001	0.29 (0.15-0.55)	<0.001
11-20 cigarettes/day	39.56 ± 0.1	0.722	0.96 (0.57-1.60)	0.869	39.88 ± 0.1	0.038	0.68 (0.42-1.11)	0.120
>20 cigarettes/day	38.90 ± 0.2	0.001	2.80 (1.56-5.01)	0.001	39.45 ± 0.1	0.195	1.60 (0.85-2.98)	0.143
Maternal smoking amount^b
None	39.60 ± 0.1	-	1.00	-	39.91 ± 0.0	-	1.00	-
1-10 cigarettes/day	38.62 ± 0.3	0.002	3.11 (1.37-7.06)	0.007	39.41 ± 0.2	0.038	2.16 (0.83-5.64)	0.115
>10 cigarettes/day	38.85 ± 0.6	0.184	4.34 (1.12-16.87)	0.034	38.74 ± 0.3	<0.001	6.76 (2.73-16.77)	<0.001
Smoking amount in both parents^b
None	39.64 ± 0.1	-	1.00	-	39.81 ± 0.1	-	1.00	-
1-20 cigarettes/day	39.64 ± 0.1	0.974	0.89 (0.56-1.40)	0.615	39.94 ± 0.1	0.167	0.88 (0.52-1.46)	0.613
>20 cigarettes/day	38.92 ± 0.2	<0.001	2.79 (1.56-4.98)	0.001	39.53 ± 0.1	0.068	1.97 (1.02-3.82)	0.045

Note. SE = standard error; OR = odds ratio; CI = confidence interval.
^aAdjusted for birth order, maternal age at delivery, father’s education, and household income.
^bAdjusted for birth order.

ISSN: 1471-2393