Women who cut down early in pregnancy were more likely to stop smoking by 36 weeks

Design

Exploratory analysis of pooled data from two randomised trials

Population

1409 pregnant smokers in two UK multicentre cessation trials

Primary outcome

Quit attempt and smoking abstinence at 36 weeks

Effect

Quit attempt: intention OR 1.50 (1.26–1.79), self-efficacy OR 1.60 (1.30–1.96); abstinence: early reduction OR 1.02 per % (1.01–1.02)

This exploratory analysis pooled 1409 pregnant smokers from two UK multicentre cessation trials and looked for baseline features that predicted a quit attempt and abstinence at 36 weeks.

Making a quit attempt was predicted by beliefs: stronger intention to quit (OR 1.50, 95% CI 1.26 to 1.79) and higher self-efficacy (OR 1.60, 1.30 to 1.96). Actually staying abstinent was predicted by behaviour: a larger percentage reduction in cigarettes early in pregnancy (OR 1.02 per percentage point, 1.01 to 1.02) and a previous quit attempt lasting longer, especially beyond six weeks.

The practical message is about timing. A woman who has already cut down at booking is showing she can change, and that is the moment to offer cessation support rather than record her as a smoker and move on. Tobacco use in Indian pregnancies is more often smokeless, which these trials did not study.

• At booking, ask how much she smoked before pregnancy as well as now, and record the reduction.
• Treat an early cut-down as readiness to quit and offer referral to cessation support at that visit.
• Ask about the longest previous quit; a gap of six weeks or more predicts success and is worth building on.
• Ask about smokeless tobacco (gutka, khaini, mishri) as well as cigarettes and bidis.
• Revisit at every antenatal visit; motivation predicts an attempt, but behaviour predicts staying quit.

Why it matters

It suggests the booking visit is where the most receptive smokers can be identified, not just recorded.

Don't overread it

These are exploratory predictors from trial participants in the UK; they do not show that targeting support by them improves quit rates.

The statistics, in plain English

An odds ratio of 1.02 per percentage point sounds tiny, but it compounds: a woman who halved her smoking has substantially higher odds of abstinence than one who did not cut down at all. The outcomes were mostly self-reported, which tends to overstate quitting.

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