The effects of loop excision of the transformation zone on cervical length: Implications for pregnancy

OBJECTIVE: This study was undertaken to determine whether previously descri bed significant and quantitative cervical shortening caused by loop excisio n of the transformation zone persists after 3 months of healing. STUDY DESIGN: A prospective study was designed in which 20 patients were en rolled. Each underwent transvaginal ultrasonography for determination of ce rvical length before the loop excision of the transformation zone and great er than or equal to 3 months after the loop excision of the transformation zone. Simple regression analysis and the Student paired t test was performe d to determine whether the length of the cervix had changed significantly b etween the measurements. RESULTS: The mean cervical lengths as measured by transvaginal ultrasonogra phy before and after loop excision of the transformation zone were 3.1 +/- 0.8 cm and 3.1 +/- 0.7 cml respectively. The correlation between ultrasonog raphic measurements before and after loop excision of the transformation zo ne was r = 0.88 (P < .0001). A paired t test resulted in a P value of 1.000 0, which indicates that the ultrasonographic measurement after loop excisio n of the transformation zone was not different from the ultrasonographic me asurement before loop excision of the transformation zone. The mean differe nce between measurements was 0.0 +/- 0.4 cm. CONCLUSION: After adequate healing time after loop excision of the transfor mation zone, the length of the cervix, as measured by transvaginal ultrason ography, does not appear to remain shortened.