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Evidence summaries

Psychosocial Interventions for Supporting Women to Stop Smoking in Pregnancy

Psychosocial interventions especially counselling, feedback and incentives are effective for smoking cessation in pregnancy. Smoking cessation is effective for reducing preterm birth, low birthweight, small for gestational age, and admissions to neonatal intensive care compared with usual care. Level of evidence: "A"

Summary

A Cochrane review [Abstract] 1 included 88 studies with over 28 000 subjects providing data on smoking abstinence in late pregnancy. Interventions were categorised as counselling, health education, feedback, incentives, social support, exercise and dissemination. In separate comparisons, there is high-quality evidence that counselling increased smoking cessation and abstinence in late pregnancy compared with usual care T1 and less intensive interventions (18 studies; average RR 1.25, 95% CI 1.07 to 1.47). A clear effect was seen in smoking abstinence in postpartum T2. Women who received psychosocial interventions had a 17% reduction in infants born with low birthweight, a significantly higher mean birthweight, and a 22% reduction in neonatal intensive care admissions T2.

Separate intervention comparisons for supporting women to stop smoking in pregnancy - Outcome: Smoking abstinence in late pregnancy

Interventions and comparisonsRelative effect(95% CI)Risk with comparisonRisk with main intervention (95% CI)of participants(studies) Quality of evidence
Counselling vs usual careRR 1.44(1.19 to 1.73)9 per 10013 per 100(11 to 16)12 432(30) High
Health education vs usual careRR 1.59 (0.99 to 2.55)8 per 10012 per 100(8 to 20)629(5) Moderate
Feedback vs usual careRR 4.39(1.89 to 10.21)4 per 10017 per 100(7 to 39)355(2) Moderate
Incentives vs alternative interventionsRR 2.36(1.36 to 4.09)16 per 10037 per 100(21 to 64)212(4) High
Exercise vs usual careRR 1.20(0.72 to 2.01)6 per 1008 per 100(5 to 13)785(1) Moderate
Social support vs less intensive interventionsRR 1.21(0.93 to 1.58)19 per 10023 per 100(18 to 31)781(7) High

Outcomes for all interventions for smoking cessation in pregnancy compared to control

OutcomeRelative effect(95% CI)Risk with controlRisk with Interventions (95% CI)of participants(studies) Quality of evidence
Abstinence in late pregnancy: self-reported and biochemically validatedRR 1.35(1.23 to 1.48)12 per 10016 per 100(15 to 18)26 637(97) Moderate
Abstinence at 0 to 5 months postpartumRR 1.32(1.17 to 1.50)131 per 1000173 per 1000(153 to 196)8366(35) High
Low birthweight (under 2500 g)RR 0.83(0.72 to 0.94)92 per 100076 per 1000(66 to 87)9402(18) High
Preterm birth (under 37 weeks)RR 0.93(0.77 to 1.11)72 per 100067 per 1000(55 to 80)9222(19) High
Mean birthweight (g)-The mean birthweight (g) was 0MD 55.60 higher(29.82 higher to 81.38 higher)11 338(26) High
NICU admissionsRR 0.78(0.61 to 0.98)118 per 100092 per 1000(72 to 116)2100(8) High

An individual participant data meta-analysis 2 assessing changes in smoking during pregnancy and risk of adverse birth outcomes included 229 158 singleton births (28 cohorts in Europe and North America). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08, 95% CI 1.02 to 1.15, P value = 0.012), small size for gestational age (OR 2.15, 95% CI 2.07 to 2.23, P value < 0.001), and childhood overweight (OR 1.42, 95% CI 1.35 to1.48, P value < 0.001). Mothers who reduced the number of cigarettes between the first and third trimester, without quitting, still had a higher risk of small size for gestational age. However, the corresponding risk estimates were smaller than for women who continued throughout pregnancy. Reducing the number of cigarettes during pregnancy did not affect the risks of preterm birth.

A dose-response analysis 3 assessing smoking and the risk of preterm birth included 25 million mother-infant pairs. Maternal smoking during pregnancy was associated with an increased risk of preterm delivery. The adjusted ORs (95% CI) of preterm birth for mothers who smoked 1-2, 6-9, 10-19, and HASH(0x2fcfe80)20 cigarettes per day during the first trimester compared with mothers who did not smoke were 1.31 (1.29 to 1.33), 1.33 (1.31 to 1.35), 1.44 (1.43 to 1.45), and 1.53 (1.52 to 1.55), respectively (all P values < 0.001), whereas for those who smoked during the second trimester, the corresponding ORs were 1.37 (1.35 to 1.39), 1.36 (1.34 to 1.38), 1.48 (1.47 to 1.49), and 1.59 (1.58 to 1.61), respectively (all P values < 0.001). Furthermore, smokers who quit before pregnancy, regardless of smoking intensity, had a comparable risk of preterm birth with nonsmokers, although this was not the case when cessation occurred in the first or second trimester of pregnancy.

Clinical comments

Note

Date of latest search: 2020-10-28

    References

    • Chamberlain C, O'Mara-Eves A, Porter J et al. Psychosocial interventions for supporting women to stop smoking in pregnancy. Cochrane Database Syst Rev 2017;(2):CD001055. [PubMed]
    • Philips EM, Santos S, Trasande L et al. Changes in parental smoking during pregnancy and risks of adverse birth outcomes and childhood overweight in Europe and North America: An individual participant data meta-analysis of 229,000 singleton births. PLoS Med 2020;17(8):e1003182. [PubMed]
    • Liu B, Xu G, Sun Y et al. Maternal cigarette smoking before and during pregnancy and the risk of preterm birth: A dose-response analysis of 25 million mother-infant pairs. PLoS Med 2020;17(8):e1003158. [PubMed]

Primary/Secondary Keywords