CERVICAL SMOOTH-MUSCLE CONTRACTILE ACTIVITY AFTER TREATMENT WITH MIFEPRISTONE AND PROGESTERONE

Contractile activity of the uterine cervix in vitro was studied in wom en pretreated with mifepristone 200 m(chi)2 or progesterone suppositor ies 200 mg before cervical dilatation and vacuum aspiration in the fir st trimester. Mifepristone increased the dilatation of the cervix as m easured prior to operation whereas progesterone had no effect. Spontan eous muscle activity and contraction frequency were not affected by ei ther drug. Neither the inhibitory response to PGE, nor the excitatory response to noradrenaline were significantly different from that in pl acebo-treated women. It is concluded that the cervical smooth muscle h as no major role in the dilatatory effect of mifepristone in the cervi cal canal.