Experimental pregnancy was induced with gonadal steroids in in vivo ovariectomized rats. Conditions for premature delivery were established by giving a salt-rich diet and administering oxytocin to induce high-risk pregnancy. In order to avoid early delivery, a betamimetic ritodrine and the Ca++ channel blockers nitrendipine and nicardipine were administered to three separate groups. The effects of these three tocolytic agents were examined by determining serum oestradiol and progesterone levels. Additionally, systolic blood pressure was measured and tachycardia was observed. After the administration of tocolytic agents, it was observed that serum oestradiol levels were increased while there was a decrease in serum progesterone levels. These three drugs cause no difference in hormone levels and can be used as tocolytic agents; however, it was observed that ritodrine carries the risk of tachycardia. Findings in the high-risk pregnancy group (hypertensive), to which no tocolytic agent was given, showed that the normal pregnancy period had not been completed.

Experimental pregnancy was induced with gonadal steroids in in vivo ovariectomized rats. Conditions for premature delivery were established by giving a salt-rich diet and administering oxytocin to induce high-risk pregnancy. In order to avoid early delivery, a betamimetic ritodrine and the Ca++ channel blockers nitrendipine and nicardipine were administered to three separate groups. The effects of these three tocolytic agents were examined by determining serum oestradiol and progesterone levels. Additionally, systolic blood pressure was measured and tachycardia was observed. After the administration of tocolytic agents, it was observed that serum oestradiol levels were increased while there was a decrease in serum progesterone levels. These three drugs cause no difference in hormone levels and can be used as tocolytic agents; however, it was observed that ritodrine carries the risk of tachycardia. Findings in the high-risk pregnancy group (hypertensive), to which no tocolytic agent was given, showed that the normal pregnancy period had not been completed.