Premature birth is considered to be the consequence of independent alterations in the cervix and in the uterus. During labor, for full-term birth, as well as for premature birth, the cervix changes, from firm, long and closed, to soft and pliable, through a biochemical process characterized by the reshaping of the extracellular matrix and a growth of the tissue concentration of inflammatory mediators; the uterus proves an increase in contractility and sensitivity to endogenic hormones, such as oxytocin. Premature labor is associated with the premature activation of the release of cytokines in the decidua (mucosa lining uterus walls) and cervix. Interleukins IL-1 beta, IL-6, IL-8 and the alpha tumoral necrosis factor increase the production and activation of matrix metalloproteinases (MMP-1, MMP-3 and MMP-9) and of cathepsin S, which digests the collagen from the extracellular matrix of the cervix, causing the wiping and softening of the cervix. These cytokines are released by leukocytes in the myometer, leading to the production of prostaglandins and oxytocin, which stimulate uterine contractions. Therefore, the cervical shortening represented by ultrasound is believed to represent premature cervical softening. The obstetrical approach of aspects related to premature birth are based, considerably, on the prognosis expected by the obstetrician regarding the survival of the premature new-born baby, as well as the therapeutic variants to be followed. And not only survival is important, of equal importance is also the quality of life of underweight, immature new-born babies, who are considerably affected both physically, and intellectually.