The object of this paper is to highlight the importance of enzymatic diagnostics in obstetrics and gynecology. Enzymatic diagnostics through the assessment of oxytocinase allows to monitor the pregnancy and predict the delivery. Oxytocinase and its isoenzymes reflect the present state of the mother, the fetus and the placenta. The constant increase of oxytocinase in maternal blood up to the time of delivery and its appropriate level indicates the proper development of pregnancy. Low lewel and above all decrease in level instead of the normal constant increase precedes by several weeks clinical symptoms of abortions and preterm deliveries. Maternal blood levels of cystine-amino-peptidases (CAP1 and CAP2) show high correlation with the fetal and placental mass as well as fetal maturity. The levels of oxytocinase allow to objectivize the duration of pregnancy and to reduce induced and operative deliveries.