While performing "Kangaroo care" the infant should be held skin-to-skin contact with her mother for 30-60 minutes. The baby, who is naked except for a diaper and a piece of cloth covering his or her back (either a receiving blanket or the parent's clothing), is placed in an upright position against a parent's bare chest. The values of heart rate variability will be measured during and also without Kangaroo Care in the same infants but different times.

Kangaroo care is a technique practiced on newborn, usually preterm, infants wherein the infant is held, skin-to-skin, with an adult.

By using Holter monitorization for 24 haur. LF (frequency domain, low frequency measurement): The low-frequency (LF) spectra represents predominantly sympathetic with some parasympathetic influence in the 0.04-to-0.15 Hz range.

By using Holter monitorization for 24 haur, 5 different measurements get by 5 minutes heart rate analysis: SDNN, SDANN,SDNN index,Rmssd,pNN50 SDNN: ms, Standard deviation of all NN intervals. SDANN: ms Standard deviation of the averages of NN intervals in all 5 min segments of the entire recording.

SDNN index: ms, mean of the standard deviations of all NN intervals for all 5 min segments of the entire recording RMSSD: ms, The square root of the mean of the sum of the squares of diVerences between adjacent NN intervals.

pNN50: % NN50 count divided by the total number of all NN intervals