The object of the study was to evaluate R. Klimek's new simple clinical method of computing newborn's maturity index (K) without having to use the computer-aided method or understand the basics of the quantum mechanics or theory of relativity, which gave rise to the modern definition of maturity. The study was based on the material of 1000 successive newborns delivered in the Clinic of Gynecology and Obstetrics of the Jagiellonian University. Their maturity was determined routinely in BK scale, and confirmed by means of computer-aided method of birth term prognosis. Posture, angle of the elbow, pulling an elbow to the middle line of the body, breast appearance, presence of lanugo and plantar creases were evaluated by means of K index with points from 0 to 2. Newborns' maturity index K was 9.2 +/- 1.9 points (range 2-12). 2.6% newborns were immature and one third of them (0.8%) were born with the gestational age < 37 weeks, 28 of which (77%) had correct K index > or = 6 points. There is a high, statistically significant correlation between maturity assessed in Ballard-Klimek scale and K index (r = 0.61, t = 24.78).

Results of prospective studies of 1404 consecutive vaginal and cesarean deliveries of newborns weighted > or = 2500 g were analyzed in relation to their maturity. It was stated that Ballard Maturation Score is a valid accurate assessment tool for precise interpretation of the degree of fetal maturity, but not of the calendar length of gestation, especially beyond 36 weeks. Therefore it was reasonable to propose a constant distribution of scores: 39 +/- 3 points within the period from 37% to 43% weeks while at the 28th week: 10 +/- 2 points (Ballard-Klimek scale of pregnancy dating) instead of therefore used J. L. Ballard rule that only newborns at 44 weeks can have scores of 50 and infants with shorter gestational age have lower values, e.g. 33 at the 37th week.

Paediatric maturity was assessed in newborns whose birth weight was above or equal to 2500 g, of 1742 women of single pregnancy who delivered vaginally, and in 81 newborns with birth weight below 2500 g, by means of Ballard method. The range of maturity was 39 +/- 3 points of Ballard/Klimek score. There were only 14 newborns with birth weight below 2500 g born before 37 gestational weeks, which is only 30.4% of all newborns with a score below 33 points. The neonatological assessment of physical and neuro-muscular maturity of the newborns, allows to determine the degree of maturity and simultaneously the obstetrical criteria (newborn weight below 2500 g and 37 weeks of pregnancy), indicate only a lower limit of possible maturity.