NITRIC-OXIDE DONORS INDUCE RIPENING OF THE HUMAN UTERINE CERVIX - A RANDOMIZED CONTROLLED TRIAL

Objective To determine whether nitric oxide donors can induce cervical ripening before surgical termination of pregnancy in the first trimes ter. Design Prospective, randomised controlled trial. Setting Departme nt of Obstetrics and Gynaecology, Royal Infirmary, Glasgow. Participan ts Forty-eight primigravid women undergoing surgical termination of pr egnancy before 12 weeks of gestation. Methods The women were randomise d to receive per vaginam before surgery either the nitric oxide donor isosorbide mononitrate, the nitric oxide donor glyceryl trinitrate, th e prostaglandin analogue gemeprost, or no treatment. Main outcome meas ures The cumulative force required to dilate the cervix to 8 mm was me asured objectively and the cervical diameter before surgical dilatatio n was recorded. Results Following isosorbide mononitrate or gemeprost, a lower cumulative force was required to dilate the cervix to 8 mm an d a higher cervical diameter before dilatation was recorded. Pretreatm ent with glyceryl trinitrate reduced the cumulative force required to dilate the cervix but had no effect on cervical diameter. Conclusions Like the prostaglandin analogue gemeprost, the nitric oxide donors iso sorbide mononitrate and glyceryl trinitrate can effect cervical ripeni ng. Nitric oxide donors may provide an alternative to prostaglandins f or cervical ripening before surgical procedures in the first trimester .