Problem: While partner support benefits breastfeeding outcomes, its impact across perinatal stages on maternal co-parenting perception is unclear.

Background: Spousal involvement plays a vital role in successful breastfeeding and maternal well-being.

Aim: This study aimed to examine the effects of spousal participation in breastfeeding interventions at different perinatal stages on maternal co-parenting perceptions and infant feeding practices for full-term infants.

Methods: Pregnant women who received antenatal care and delivered at our hospital, together with their partners, were recruited and categorized by the timing of partner involvement in breastfeeding activities: both antenatal and postnatal (Group A); antenatal only (Group B); postnatal only (Group C); and no antenatal education but routine postnatal guidance (Group D). Maternal breastfeeding self-efficacy and coparenting perception were assessed at 6, 12, and 24 weeks postpartum.

Inclusion Criteria:

• Married couples, with gestational age between 12 - 14 weeks at enrollment for Groups A and B;
• Planned discharge within 48 hours after delivery;
• Mothers and partners expected to cohabit for ≥6 months postpartum;
• Gestational age at delivery ≥37 weeks;
• No diagnosed psychiatric disorders in either partner;
• Voluntary participation with written informed consent from both mother and partner;
• Neonates with Apgar scores ≥8 at 1, 5, and 10 minutes after birth.

Exclusion Criteria:

• Maternal diagnosis of infectious diseases (e.g., HIV, hepatitis B);
• Withdrawal from the study at any stage;
• Failure to complete required questionnaires;
• Loss to follow-up during the study period;
• Concurrent participation in other interventional studies;
• Major fetal anomalies.