[Physiology of uterine contractions (author's transl)].

The number of contractions was recorded in 26 healthy primiparae and 28 multiparae from the 25th to 41st week of pregnancy. A remarkable incidence peak was seen around the 32nd week. The number of pregnancy contractions is not sufficient as the only parameter for recognising an impending premature delivery. However, it does represent a valuable aid when taking the anamnesis and portio findings into consideration. The authors consider tocolysis indicated if more than two contractions per hour are recorded as mean value over a period of one week in conjunction with a tendency of the portio to open up, or if more than three contractions are recorded independent of this sign. Taking individual daily into consideration, the relevant limit is three contractions per hour between the 25th and 28th week, and five contractions per hour between the 29th and 32nd week of pregnancy.