(A) clinical study of incompetent internal os of the cervix
This study was undertaken for the clinical analysis and evaluation on the women
with I.I.O.C. who were admitted and treated at the Yonsei University Medical Center
from Jan. 1, 1964 to Dec. 31, 1972.
The Followings were the results of this study.
1) I.I.O.C. encountered approximately once in every 265 deliveries.
2) The most frequent age incidence was from 25 to 34 age group, and most of them
had a history of 2 or more previous immature or premature deliveries.
3) Previous history of induced absortion was found to be a significant
contributory factor in 29 of 56 cases of I.I.O.C.
4) The surgical success rate was inversely proportional to the degree of the
dilatation or effacement of the cervix.
5) Those cases which were found during non-operation were corrected by Lash
operation, those which were diagnosed during pregnant state were corrected by
Shirodkar operation and only one case received McDonald operation.
Most of them were performed between 12 and 20 gestational weeks and its success
rate was much higher than other times.
6) The fetal salvage rate was 66.7%