This study proposes a prospective randomized controlled clinical trial involving primiparous women diagnosed with gestational diabetes mellitus (GDM) carrying singleton pregnancies. Participants will be randomized in a 1:1 ratio into either a control group or an intervention group.

The control group will receive standard prenatal care followed by routine postpartum breastfeeding guidance.

In addition to the standard care provided to the control group, the intervention group will receive one-on-one midwife-led manual breast milk expression training at the breastfeeding clinic. They will begin manual expression twice daily starting at 37 weeks gestation.

The primary outcome will compare exclusive breastfeeding rates at 3 months postpartum between groups through postpartum follow-up assessments to evaluate the impact of antenatal milk expression on breastfeeding success in GDM patients.

Inclusion Criteria:

• Expressed intention for exclusive breastfeeding; Aged 20-45 years; Nulliparous status; Singleton pregnancy; GDM diagnosed per 75g OGTT at 24-28 weeks

Exclusion Criteria:

• Contraindications to breastfeeding; multifetal pregnancy; placenta previa; pregestational diabetes mellitus; preeclampsia; contraindications to vaginal delivery; fetal structural anomalies (cleft lip/palate, cardiac malformations, neural tube defects); chromosomal abnormalities or metabolic disorders affecting suckling ability (e.g., phenylketonuria); intrauterine growth restriction; macrosomia; polyhydramnios; maternal psychiatric disorders (depression or anxiety disorders)

Biologically female individuals capable of conception and childbirth