[The uterine contraction stress test with oxytocin nasal spray in the diagnosis of hypoxemia].

Deceleration of the fetal heart rate are indications of fetal distress, which are commonly seen in connection with uterine contractions. The aim of the investigation was, whether nasal application of oxytocin (Syntocinon, Sandoz AG) is sufficient for the induction of contractions for an oxytocin-challenge-test. 232 oxytocin-challenge-tests in 85 risk patients between 29th-42nd week of gestation were analyzed in a retrospective and prospective way. The amounts of oxytocin nasal spray necessary for stimulating contractions were compared to the gestational age and maternal body weight (1 spray snuff = 4 IU Oxytocin). 20 pregnant women were given 8 IU oxytocin nasal spray after 10 minutes CTG-registration without any contractions. The incidence of induced contractions per ten minutes period were calculated. The amount of oxytocin nasal spray necessary for the stimulation of contractions decreased in relation to the increased gestational age and maternal body weight (oxytocin spray = 2.751-0.051 X (gestational age)-0.014 X (body weight), p less than 0.01). After a single application of 8 IU oxytocin nasal spray at least one contraction occurred in 13 out of 20 cases within the first 10 minutes. Between the 20th-30th minute the induced uterine contractions reached a maximum of 3 contractions per 10 minutes. No persisting contractions were observed. The application of 8 IU of oxytocin nasal spray is sufficient to induce in about 95% of the cases an oxytocin-challenge-test which gives information concerning the actual state of the fetus at risk.