Table 1 Interventions and starting time for each intervention

Informational materials and education about breast milk feeding

1. Reinforcement of importance of breastfeeding on late preterm infants

2. Knowledge and technique to optimize breast milk production

Consultations and support on optimal breast milk initiation

1. Knowledge and technique to optimize breast milk production

2. Direct mothers with the use of breast pump

3. Nurses and volunteers supported the manual expressing and pumping of breast milk

Initiate breast milk expression within 1 h after birth

1. Knowledge and technique to optimize breast milk production

2. Nurses and volunteers supported the manual express and pumping of breast milk

Accurate measurement and recording of expressed breast milk

1. Provide milk volume recording charts to

lying-in woman

2. Provide syringe for accurate measurement of breast milk to lying-in woman

3. Remind lying-in woman to measure and record the expressed breast milk the day before D7

Stimulate continuous and effective lactation

1. Provide mothers with videos of their hospitalized infants

2. Kangaroo care in the NICU

Proper breast pump selection in and out of hospital

1. Provide consultations on selection of pump

2. Provide hospital-grade pump and instructions

Optimize sending and preserving of expressed milk to NICU

Optimize the process of sending and preserving of own mothter’s breast milk to NICU