Smoking during pregnancy: Childbirth and Health Study in Primary Care in Iceland

Figures & data

Table I. Characteristics of participants in the Childbirth and Health Study 2009–2010 (percentages and absolute figures in parentheses or as otherwise described): Similar variables are shown for the entire birth cohort in Iceland in 2009.¹

	Participants (n = 1111)	Iceland (n = 4939^2)
Parity:
Primipara	40 (439)	40 (2005)
Multipara	60 (671)	60 (3021)
Age:
18–19	2 (18)	3 (185)
20–24	15 (168)	17 (841)
25–29	36 (405)	34 (1691)
30–34	30 (328)	29 (1434)
35–39	14 (155)	14 (722)
> 40	3 (37)	3 (168)
Mean age (yrs)	29.4	29.7
Education:
Elementary	11 (123)	28^3 (18 000)
High school or similar	26 (291)	36^3 (23 100)
Technical education or university < 4 years	26 (291)	X^4
University > 4 years	36 (404)	36^3,5 (23 100)
Combined higher education^6	89 (986)	72^3 (46 200)
Residence:
Capital area	69 (763)	67 (3378)
Rural area	31 (347)	33 (1648)
Marital status:
Married/cohabiting	93 (1032)	84 (4241)
Single	3 (31)	X^4
Other	4 (48)	16 (785)

Notes: ¹Statistics Iceland, http://www.hagstofa.is (last checked on 2 April 2013). ²All deliveries in Iceland in 2009 (Icelandic Birth Register for 2009). ³Figures for pregnant women not available, but only for the total sample (n = 64 000) of all Icelandic women aged 20–49 years. ⁴No figures for comparison available. ⁵Counts all university education regardless of duration. ⁶All education after elementary school.

Table II. Characteristics of women who quit smoking while pregnant and those who smoke during early pregnancy (means and standard deviation [SD] in parentheses, and percentage and absolute figures within parentheses respectively).

	Stopped smoking during pregnancy (n = 170)	Smoked during early pregnancy (n = 53)	p-values
Number of cigarettes per day before pregnancy; mean (SD)	8 (5.3)	15 (5.2)	< 0.001
Mean age, years (SD)	28 (4.8)	28 (6.0)	0.466
Multiparous	48 (82/170)	60 (32/53)	0.123
Marital status:			0.473
Married/co-habiting	84 (142/170)	79 (42/53)
Single	17 (28/170)	21 (11/53)
Education:			< 0.001
Elementary school	20 (33/169)	42 (22/53)
Higher education	81 (136/169)	59 (31/53)
Employment status:			0.065
Receiving welfare	9 (15/170)	19 (10/53)
Working	71 (120/170)	55 (29/53)
Housewife	1 (2/170)	4 (2/53)
Student	17 (28/170)	15 (8/53)
Other	3 (5/170)	8 (4/53)
Use of medications during pregnancy:
Nicotine replacement therapy	3 (4/163)	21 (10/47)	< 0.001
Psychotropic medications^1	7 (11/163)	14 (7/49)	0.097
Alcohol consumption during pregnancy	2 (3/170)	2 (1/53)	0.953
Alcohol consumption prior to pregnancy:			0.133
Rarely	55 (93/170)	68 (36/53)
Once a week or less	35 (60/170)	23 (12/53)
More than once a week	7 (11/170)	9 (5/53)
Never	4 (6/170)	0
Major life events last 12 months^2	42 (71/170)	34 (18/53)	0.311
Depressive symptoms^3	7 (12/169)	11 (6/53)	0.326
Own perceived health:			0.423
Excellent/very good	79 (135/170)	74 (39/53)
Fair	17 (29/170)	25 (13/53)
Poor/very poor	4 (6/170)	2 (1/53)
Planned pregnancy:			0.312
Yes	56 (94/168)	45 (24/53)
No, but welcome	31 (52/168)	43 (23/53)
No, the timing could have been better	8 (14/168)	9 (5/53)
No, I considered termination of the pregnancy	5 (8/168)	2 (1/53)
Information about harm of smoking in pregnancy:			0.097
None/not enough	17 (28/167)	8 (4/53)
Enough/too much	83 (139/167)	93 (49/53)

Notes: ¹Psychotropic medications: hypnotic, antidepressant, or sedative medications. ²Major life events: ≥ 2 of the following life events: having been in a serious accident or had serious illness, serious illness, accident to or death of a family member, serious concerns about a family member, divorce or separation, forced to move household or change jobs, made redundant, had feelings of insecurity at work, serious financial problems, been legally prosecuted. ³Edinburgh Postnatal Depression Scale (EPDS) ≥ 15.

Table III. Factors predictive of continued smoking in pregnancy: Logistic regression analysis.

	Adjusted OR (95% CI)^1	p-values	B
Lower level of education	2.5 (1.2–5.5)	0.021	0.918
Increased number of cigarettes smoked per day before pregnancy	1.2 (1.1–1.3)	< 0.001	0.201
Married	0.8 (0.3–2.1)	0.664	− 0.213
Depressive symptoms^2	1.6 (0.4–6.1)	0.474	0.482

Notes: ¹95% confidence interval. ²Edinburgh Postnatal Depression Scale (EPDS) ≥ 15.