Inclusion Criteria:  Babies born alive before 37 weeks of pregnancy, and in the case of twins, the body weight heavier babies will be the first to be admitted. Infants who were required to receive heel lance procedure every 8 hours after physicians' diagnoses. Those who can record the mother's voice and whose mother can read Chinese.  Exclusion Criteria:  Abnormal ear appearance, chromosomal abnormalities, congenital or acquired infections. Postnatal patients whose mothers are not in the postnatal ward, e.g., those who need to be admitted to the intensive care unit due to their medical condition. Patients used high-frequency oscillatory ventilators, because the high-frequency oscillatory ventilator gives 600 oscillatory breaths per minute and it is not possible to evaluate whether the study subjects can effectively listen to the interventions given, so they were excluded. Mothers who were unable to complete the recording because of emotional ups and downs during the recording process. Mothers who smoked, drank alcohol or used illegal drugs during pregnancy. the patients was diagnosed with Asphyxia of the newborn at birth Painkillers used within 3 days of birth.