Table 1.

Intervention and research participation incentives

Time point	Intervention	Control
Initial local smoking cessation services meeting and setting quit date	£50 voucher	N/A
Verified quit at 4 weeks after quit date	£50 voucher	N/A
Verified quit at 12 weeks after quit date	£100 voucher	N/A
Verified quit at 34–38 weeks gestation and provision of urine/saliva sample if quit	£200 voucher	N/A
Providing data for primary outcome	£50 voucher for research participation	£50 voucher for research participation
Providing data for secondary outcome (quit 6 month postpartum)	£25 voucher for research participation	£25 voucher for research participation