Methods	Ershoff 1989 trial data of relapse prevention in the women who had spontaneously quit smoking in early pregnancy
Participants	The pre-pregnancy smokers who had quit spontaneously before the first antenatal contact: 110 + 108, with losses due to termination (5); miscarriage (17) and transfer to alternative prenatal care (25) leaving 87 + 84
Interventions	See Ershoff 1989 except that the intervention group received the first 4 booklets at the first interview with booklets 5 to 8 mailed weekly thereafter; control group were congratulated on quitting and given a tip sheet on “staying quit”. Intensity rating: I = 3, C= 2
Outcomes	Smoking data validated with urinary cotinine measurement, no perinatal data
Notes	Detailed process evaluation and analysis of factors promoting or inhibiting cessation and maintenance of non-smoking
Risk of bias
Item	Authors’ judgement	Description
Adequate sequence generation?	No	No information.
Allocation concealment?	No	See Ershoff 1989 above.
Blinding? Women and clinical staff	No	Neither caregiver nor women were blinded.
Incomplete outcome data addressed? All outcomes	No	22% attrition. No ITT analysis.
Free of selective reporting?	Unclear	None apparent.
Free of detection bias?	Yes	Biochemical validation by urinary cotinine levels.