The contractile response of the pregnant human uterus to posterior pituitary extract: A study of 375 injections recorded with the Lóránd tocograph

Abstract

1.1. A series of 96 women at various stages of pregnancy and labor received 375 hypodermic injections of posterior pituitary extract not exceeding 3 minims per dose. During treatment a continuous record was made of their uterine contractions with a Lóránd tocograph.2.2. Forty-seven per cent of treatments elicited no uterine response.3.3. An increased frequency of response was noted more often: (a) in multigravidas than in primigravidas, (b) during than before labor, (c) later in pregnancy than earlier, (d) after the larger than the smaller doses of pituitary extract, and (e) when the uterine wall was tense than when it was relaxed.4.4. The tetanic type of response occurred most often: (a) when the dose was large, and (b) when the uterine wall tension was high.5.5. Complete tetanic contractions occurred most often: (a) when the uterine wall tension was high.6.6. From this study the following conclusions are drawn: (a) That the amount of posterior pituitary extract employed, and the degree of tension of the uterine wall at the time of treatment, are two important factors to be considered when attempting to avoid an unsatisfactory type of uterine contraction during pregnancy and labor. (b) That during pregnancy and labor the most efficient type of uterine contraction is produced by the administration of small doses of pituitary extract. (c) That whether or not the drug should be employed, and how much should be used, during pregnancy or labor should not be decided without considering the degree of tension of the uterine wall.