ABSTRACT
OBJECTIVE:Our goal was to evaluate the clinical characteristics and statistical analysis in incompetent internal os of the cervix(IIOC) METHOD: At Department of Obstetrics and Gynecology, Eulgi Hospital and Eulgi university Hospital from January 1, 1991 to December 31, 1997, 296 cases of IIOC were admitted and treated with McDonald operation or modified Shirodkar operation. Of this, 38cases were follow up lost, so 252 cases were analayzed. Diagnostic criteria was previous history of painless cervical dilatation, followed by spontaneous abortion or preterm birth, and acceptance without resistance at the internal os of No. 8 Hegar dilator. RESULT: Incidence of IIOC was 1.61%, 1 in 60 deliveries. Most frequent age group was in 28-30 years old group and mean age was 30 years old. Total number and mean number of gravida was 818 and 3.2. The most common contributing factor was previous artificial abortion(77%), and cervix dilatation(9%), old cervical laceration(4.3%) etc, was followed. Operation methods were McDonald operation(56%) and modified Shirodkar operation(44%). The Success rate of McDonald and modified Shirodkar was 78.1% and 88.1%. Successful fetal salvage rate was 82.5%, and the highest success rate was 86.9% in 14-18th weeks of gestation group. The more cervix dilate, the more failure occured. Causes of operation failure was premature rupture of membrane(54.5%), preterm labor(43.2%) and fetal death in utero(2.3%). Delivery method after operation was vaginal delivery(146cases, 70.9%) and cesarean delivery(60cases, 29.1%). Cause of cesarean delivery was previous cesarean section(43.3%), breech presentation(16.7%), cephalopelvic disproportion(15%), prolonged labor(6.7%), fetal disttess(6.7%), twin(5%), placenta previa(3,3%) and abruptio placenta(3.3%). CONCLUSION: The 14-18th weeks of gestation group & no cervical dilatation group has higher success rate, which indicate early diagnosis and appropriate timing of operation is probably associated with a greater operation