Myometrial response to a long-acting vasopressin analogue in early pregnancy.

Intrauterine pressure was recorded for 4 to 6 hours in 21 healthy women having a therapeutic abortion at 6 to 9 weeks gestation. Fourteen of the women received an intravenous injection of 300 microgram of N-alpha-triglycyl-(8-lysine)-vasopressin (TGLVP) and seven were used as controls. Uterine tone and the amplitude and duration of uterine contractions increased in all women receiving the drug, uterine tone usually rising first, with a change in contractions as a secondary effect which lasted for the rest of the observation period. Uterine activity did not change in the controls. These results suggest that TGLVP might be used for the induction of abortion during the first trimester of pregnancy.