The objective of this randomized controlled trial is to examine the efficacy of a new intervention to prevent postpartum smoking relapse and related health consequences through breastfeeding promotion. After the pre-test, ex-smokers who are still abstinent from smoking will be randomized into either the breastfeeding intervention or the attention placebo control group. The outcomes are postpartum smoking relapse, breastfeeding practices, and maternal and child health.

We propose a randomized controlled trial to reduce postpartum smoking relapse by breastfeeding promotion from late pregnancy to 12 months postpartum. We will enroll 280 pregnant mothers who successfully quit smoking during this pregnancy (≤28 weeks). After the pre-test, participants who are still smoking abstinent will be randomized into either the breastfeeding intervention group (N=140) or the attention control group (N=140). The intervention group will receive a multicomponent intervention consisting of breastfeeding education, lactation counseling, social support, contingent financial incentives, and early limited formula milk via syringe feeding (optional for at-risk infants). The control group will receive counseling and support focusing on general infant care, with attention and monetary earnings similar to the intervention group. Both groups will receive usual care (i.e., information, education, and Quitline) for postpartum smoking relapse. The outcomes are postpartum smoking relapse, breastfeeding practices, and maternal and child health.

Aim 1 is to examine the efficacy of breastfeeding promotion intervention on postpartum smoking relapse. Aim 2 is to examine potential mediating mechanisms: reductions in stress and negative affect, enhancing mother-infant bonding and maternal sensitivity, and maternal weight retention. Aim 3 is to assess the effects of breastfeeding promotion intervention on maternal and infant health among ex-smoking mothers. This innovative study can yield promising data to support a new intervention to prevent postpartum smoking relapse. It has the potential to reduce smoking-related harms to both the mother and the infant, maximize the protective effects of breastfeeding on infant health and development, and narrow health disparities.

Inclusion Criteria:

• Be pregnant
• Be 18 years or older
• Have quit smoking cigarettes during this pregnancy
• Be willing to receive infant care and breastfeeding education
• Be able to read, listen, and talk in English

Exclusion Criteria:

• Medical conditions contraindicating breastfeeding, such as HIV infection, active tuberculosis, and breast removal
• Current heavy drinking (≥4 standard drinks on any day or ≥8 standard drinks per week)