Misoprostol induces cervical nitric oxide release in pregnant, but not in nonpregnant, women.
OBJECTIVE
The cells of the human uterine cervix synthesize nitric oxide, which may be a factor in cervical ripening. We studied the effect of misoprostol on cervical nitric oxide release in nonpregnant and pregnant women.


METHODS
Seventy-two nonpregnant (n=15) and pregnant (n=57; 26 in early pregnancy, 31 in late pregnancy) women were treated with either vaginal misoprostol (n=54) or vaginal placebo (n=18). The dose of misoprostol was 400 mug in nonpregnant and early pregnancy group, and 25 mug in late pregnancy group. Serial cervical fluid samples, collected before and up to 3 hours after misoprostol/placebo, were assessed for the concentration of nitric oxide metabolites by means of the Griess reaction.


RESULTS
Placebo had no effect on cervical fluid nitric oxide metabolite level. In 1 to 3 hours, misoprostol induced 4.3- to 5.2-fold elevations in cervical fluid Nox concentrations in early pregnancy (P < .01), and 4.4- to 18.2-fold elevations in late pregnancy (P < .01), but these responses did not differ significantly from each other. Misoprostol had no effect on cervical fluid nitric oxide metabolites in nonpregnant women. There was a trend towards a relationship between cervical nitric oxide stimulation after misoprostol and cervical ripening.


CONCLUSIONS
Vaginal misoprostol stimulates cervical nitric oxide release in pregnancy. This suggests a joint action of nitric oxide and prostaglandins in cervical ripening.
Väisänen-Tommiska
Mervi
M
Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Finland.
Mikkola
Tomi S
TS
Ylikorkala
Olavi
O
D000282:Administration, Intravaginal; D000328:Adult; D001826:Body Fluids / Q000737:chemistry; D020070:Cervical Ripening / Q000502:physiology; D002584:Cervix Uteri / Q000378:metabolism*; D005260:Female; D006801:Humans; D008875:Middle Aged; D016595:Misoprostol / Q000008:administration & dosage / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D010120:Oxytocics / Q000008:administration & dosage / Q000494:pharmacology*; D011247:Pregnancy
D010120:Oxytocics; D016595:Misoprostol; D009569:Nitric Oxide