Inclusion criteria:
Pregnant women aged 18-35 years at any gestational age
A singleton pregnancy with a normal and live embryo
Wanted pregnancy
Pregnancy constipation background based on the ROME III index
Literacy
No record of chronic constipation and digestive disorders, such as irritable bowel syndrome, anal fissure, rectal prolapse, intestinal obstruction and skin disease
No record of infection and local lesion in the ear area
No recent use of pharmaceutical or non-pharmacological methods to reduce constipation
Not record of active or passive smoking
Exclusion criteria:
Suffering from chronic constipation, requiring medicine interventions (e.g., emollient, cassia, fig, hedge mustard, and Fusion herbal syrup)
Digestive disorders, such as irritable bowel syndrome
Psychological treatment history (medicine and mental treatment)