The present study aimed to determine whether infants disorders of regulation of states are associated with perinatal anxiety, and further to explore the efficacy of the behavioral intervention in enhancing positive interactions between mothers and their infants and thus ameliorating infants' disorders of regulation of states.

The subjects were recruited from the hospitalized pregnant women waiting for delivery from the department of gynecology and obstetrics of the first affiliated hospital of Xi'an Jiaotong university. A total of 200 perinatal anxiety women were divided to two group(behavioral intervention group and control group) according to mental health assessment. Inclusion criteria were applied: 1. mother aged 18-40 years; 2. First-time mother, full-term and singleton pregnancy; 3.the Hamilton Anxiety Scale(HAMA) score ≥14; 4.birth with no intrapartum complications; and 5. Apgar score > 8 at the first, fifth, and tenth minutes after birth. Exclusion criteria were as follows: any mental illness besides anxiety, maternal medical illness, hypertension, advanced liver disease, renal failure, cancer, valvular heart disease, heart failure, stroke,atrial fibrillation, peripheral arterial disease, and other severe diseases.Preterm infants (< 37 weeks gestation) and multiple births were excluded from the current analysis. All the subjects completed the infants behavior and regulation of states assessment by the NBAS and were followed to 8 weeks postpartum. Mother-newborn pairs were randomly divided into NBO intervention group and control group. NBO intervention was performed once a week until 2 months. 2 ml peripheral blood was collected in the pregnant woman before delivery and in the newborns within 3 days postpartum.The serum fraction was removed after centrifugation and stored at -20°C. Levels of serum cortisol in mothers and newborns were determined using Chemiluminescence analysis (CLIA) and a radio immunoassay. All sample analyses were performed by the first affiliated hospital of Xi'an Jiaotong university chemistry laboratory. Laboratory personnel were blinded to mother and infant outcomes.

Inclusion Criteria:

• mother aged 18-40 years;
• first-time mother, full-term and singleton pregnancy;
• the Hamilton Anxiety Scale(HAMA) score ≥14;
• the birth with no intrapartum complications;
• Apgar score > 8 at the first, fifth, and tenth minutes after birth.

Exclusion Criteria:

• any mental illness besides anxiety, maternal medical illness, hypertension, advanced liver disease, renal failure, cancer, valvular heart disease, heart failure, stroke, atrial fibrillation, peripheral arterial disease, and other severe diseases;
• preterm infants (< 37 weeks gestation);
• multiple births;
• infants with congenital anomalies, signs of illness, or high-risk factors.