RESUMEN
Objective: To determine the changing of trend in methods of delivery in a university hospital, the correlation among each method of delivery as well as the correlation of the cesarean section rates and the perinatal mortality rates. Methods: The medical records of birth in Siriraj Hospital during 1979-2006 were collected and analyzed. The methods of delivery from these data were grouped and categorizes as following : vaginal delivery, cesarean section, forceps extraction, vacuum extraction, vaginal breech delivery and others. Each method of delivery was studied separately in detail for time and accordingly trend and comparatively to the others to find interaction among them. The changing of trend of perinatal mortality rates were also demonstrated to identify the correlation with the cesarean section rate. Results: There were totally 442,635 births for this study. It was found that the percentage of vaginal delivery was decreased from 82.35 % in 1979 to 58.44 % in 2006 while the cesarean section rates was increased steadily from 7.06% in 1979 to 37.77 % in 2006. The other methods of delivery such as forceps extraction, vacuum extraction and vaginal breech delivery do not play significant roles in this changing trend since they have only small proportions ranging from about 2-5% of all deliveries. In the view of perinatal mortality rate , it continuously declined and has been less than 10% in the last 10 years. Conclusion: Regarding to 28-year review, it is clearly established that methods of delivery are now changing. Cesarean section rate rises steadily with unpromising sign of stabilization and is now far beyond the rate suggested by WHO. It directly effects the downward trend of vaginal delivery and also may be to the other methods of delivery such as vaginal breech delivery, forceps extraction and vacuum extraction, approaching the extinction. This study found no significant correlation between the increasing cesarean rates and the perinatal mortality rates.