The role of antibiotic therapy in the prevention of prematurity

The results of most studies demonstrate neither a significant change in the overall preterm delivery rate nor a significant contribution to improvement in neonatal outcome in the antibiotic groups. Only a limited prolongation in duration of pregnancy was demonstrated in several studies. These disappointing results are apparently in contradiction to the hypothesis that infection plays a major role in the pathophysiology of PTL. Several potential explanations can be evoked to interpret this discrepancy. First, in most studies the number of patients enrolled was small and the negative results can be attributed to this fact. It was estimated that there is a need for a sample size of 2270 to detect 33% reduction in neonatal outcome between the antibiotics and the placebo groups. Second, most studies administered antibiotics to all patients presenting with PTL, without performing amniocentesis for detection of intraamniotic infection. Noted that most patients presenting with PTL have no clinical signs or symptoms of infection and that the only way to detect intraamniotic infection is by performing amniocentesis. Because intra-amniotic infection occurs in 10% to 20% of patients who have PTL, only this subgroup may benefit from administration of antibiotics. Needless to say, the types of micro-organisms involved have great importance in selecting the type and the regimen of antibiotic therapy. Thus, it does not seem logical that the administration of antibiotics can be the universal treatment for the heterogenic condition such as problem of PTL. There is an urgent need for well-designed studies that should be addressed based on early and accurate diagnosis of intraamniotic infection and appropriate randomization of patients after AF-culture results.