The treatment of threatened premature labor by drugs

There are many reports describing the extent of uterine excitement in vitro and clinical conditions of uterine contractions at the time of threatened premature labor. Changes in blood levels of c-AMP, Ca and PG appear to be the most useful parameters for uterine contraction and relaxation. 1) The blood level of c-AMP during threatened premature labor increased when any of the uterine inhibitors went administered. 2) An inhibitory effect was also seen with intravenous administration of dibutyryl c-AMP, an analogue of c-APM. When the inhibitory effects against threatened premature labor by various inhibitors were classified by their inhibitory pattern, terbutaline and dibutyryl c-AMP had the a strongest and quickest effect, whereas ethanol and indomethacin were weaker and slower in promoting the onset of their activities. 3) Analysis of 263 cases of threatened premature labor treated in our department in the past 5 years demonstrated that there are 2 phases of contraction during premature labor. They are the active phase and the depressed phase. The active phase is best treated with beta 2-stimulants whereas the drug of choice for the depressed phase can be varied to suit the clinical situation.