Box 1.

Recruiting women to the study

• All pregnant women attending their first antenatal appointment in the three participating trusts were asked by midwives using a “show card” to indicate which best described their smoking status: “I smoke now”; “I smoke now but have cut down since I thought I might be pregnant”; “I have stopped smoking since I thought I might be pregnant”; “I do not smoke”
• Women who smoked before becoming pregnant (first three response categories above) were eligible for recruitment if they were aged 16 years or over, less than 17 weeks pregnant, and able to speak sufficient English
• All eligible women provided written consent to participate in the trial