Changes in the coelomic fluid composition following two different methods of cervical ripening

We have evaluated the changes in maternal serum and coelomic fluid biochemical composition following two different methods of cervical ripening, i.e. mechanical and biochemical. Each study group included 20 women between 8 and 12 weeks of gestation who were requesting termination for psychosocial reasons. In the first group, a 3 mm hypan (synthetic hygroscopic dilator) was inserted into the cervix 12 h preoperatively. In the second group, two 1 mg pessaries of gemeprost (prostaglandin analogue) were inserted into the posterior fornix 6 and 2 h preoperatively. Coelomic fluid and maternal serum were obtained at the time of the surgical procedure and assayed for urea, total protein, potassium, sodium, human chorionic gonadotrophin (HCG) and alpha-fetoprotein (AFP). Significantly higher coelomic fluid sodium (t = 4.72; P = 0.029) and significantly higher maternal serum AFP (t = 13.21; P < 0.001) concentrations were observed after gemeprost than after hypan. There was no difference in the concentration of potassium, urea, total protein and HCG between the two groups. These findings indicate that prostaglandin analogues, when used for cervical ripening, provoke a breakdown of the placental barrier resulting in an increase in AFP molecules transferred from the fetal fluid compartments into the maternal circulation. The results also suggest that these drugs increase the placental permeability to sodium with a secondary accumulation of this ion in the coelomic fluid.