Accurate assessment of mother & infant sleep: how many diary days are required?

Purpose: The purpose of the study was to determine the number of days of diary data collection needed to reliably measure mother and infant sleep-wake pattern.

Study Design And Methods: Twenty healthy adult mothers and their healthy term gestation infants age 4 to 10 weeks postnatal participated in a single group, cross-sectional design. Mothers completed a paper and pencil sleep-wake diary divided into 15-minute time periods. Data were collected in the home environment over a 4-day period. Mother and infant sleep and wake as well as infant feeding and cry were summarized and compared using between 1 and 4 days of data. Reliability was evaluated by correlating results obtained using from 1 to 4 days of data.

Results: Mean values for mother and infant sleep and activity variables did not differ significantly by day. Correlation among values calculated using increases in number of days of data showed adequate reliability (r > or = 0.80) when 3 days of data were used.

Clinical Implications: Clinical measures should be valid and reliable. Due to day-to-day changes in maternal and infant sleep-wake pattern, a diary collected over 1 day may not provide adequate sleep information. These study findings indicate that 3 days of diary data are sufficient to reliably measure mother and infant sleep patterns. When using a diary to assess maternal and infant sleep-wake pattern in clinical practice or in clinically-based research, a 3-day period is suggested.