The effect of a Foley catheter balloon on cervical ripening

The Foley catheter balloon may affect cervical ripening through changes in biochemical mediators by immunoassay and immunohistochemistry, when it is used for pre-induction cervical ripening. The aim of the study was to evaluate the changes in the biochemical mediators from the extra-amniotic space and immunohistochemistry in ripened cervical tissue after the insertion of a Foley catheter balloon (FCB) for pre-induction cervical ripening. A total of 18 pregnant women with a Bishop's score < 6, who were undergoing labour induction, were evaluated in this prospective study. The FCB was irrigated with 10 ml of phosphate buffered saline and the irrigant was collected 0, 2, 4 and 8 h after placement of the FCB or until spontaneous expulsion of the FCB occurred. Irrigant specimens were also collected from 10 spontaneous labouring (SL) women in the active phase of labour. The levels of interleukin (IL)-6, IL-8, matrix metalloproteinase (MMP)-8 and NO were measured. Cervical specimens were obtained from 12 women, including four undergoing induction; four SL and four non-pregnant (NP) women. Immunohistochemical staining was performed to localise hyaluronic acid synthase (HAS)-1, IL-6, IL-8, MMP-8, endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS). Results showed that the levels of IL-6, IL-8, and MMP-8 significantly increased over time in FCB group (p < 0.01). In the immunohistochemical analysis of cervical tissues, immunoreactivity of HAS-1 in the after FCB group was stronger than any of the other groups. The protein expressions of IL-6, IL-8, MMP-8, eNOS and iNOS were more prominent in the after FCB and SL groups than in the NP and the before FCB groups. iNOS was only observed in the after FCB and SL groups. It was concluded that FCB may affect cervical ripening through changes in biochemical mediators by immunoassay and immunohistochemistry, when it is used for pre-induction cervical ripening.