Subclinical intra-amniotic infection in asymptomatic patients with refractory preterm labor.

The purpose of this prospective investigation was to determine the incidence of subclinical intra-amniotic infection in asymptomatic patients who had intact membranes and refractory preterm labor. Refractory preterm labor was defined as persistent uterine contractions despite maximum recommended doses of parenteral tocolytics, or recurrent preterm labor within three days of successful transition to oral tocolytics. Amniotic fluid was cultured aerobically and anaerobically and prepared for Gram stain and group B streptococci latex fixation test. One of 24 women had a positive latex fixation test, but the culture was negative. One culture was positive for isolated colonies of Corynebacterium sp. None of the patients developed clinical evidence of intra-amniotic infection or postpartum endometritis. The mean prolongation of pregnancy was 31 days (range 1-63). None of the infants had evidence of sepsis in the immediate neonatal period. In this population, subclinical infection was an uncommon cause of refractory preterm labor.