Intraamniotic infection in patients with intact membranes and preterm labor

The purpose of this review was to determine the frequency of intraamniotic infection in women with preterm labor and intact membranes and to assess the need for amniocentesis in these patients. We reviewed reports in the English language literature from the past 10 years in which the frequency of intraamniotic infection was determined by transabdominal amniocentesis. The 16 studies reviewed demonstrated frequencies of positive cultures that varied from 0 to 61 per cent. This extreme variability seems to be the result of diverse patient populations, dissimilar microbiologic techniques, and different definitions of preterm labor. Advanced cervical dilation and poor response to tocolytic agents were two factors associated with a higher frequency of intraamniotic infection. We conclude that each institution must determine the frequency of intraamniotic infection associated with preterm labor in their patient population. In populations with a high frequency of infection, amniocentesis for microbiologic evaluation is recommended for management of preterm labor, especially in patients who have advanced cervical dilatation or who are unresponsive to tocolytic therapy.