FIELD: medicine.SUBSTANCE: invention relates to medicine, namely obstetrics and laboratory diagnostics, and can be used to predict the onset of preterm delivery at the gestation period of 24–34 weeks. In pregnant women with a period of 24–34 weeks of gestation in the blood plasma, the concentration of bacterial lipopolysaccharides is determined. With the value of this indicator more than 8.36 EU/ml predict the onset of preterm delivery.EFFECT: method allows for accurate, simple and affordable prediction of the onset of preterm delivery, to reduce perinatal mortality, to choose the tactics of pregnancy management in due time by estimating the concentration of bacterial lipopolysaccharides in the blood plasma.1 cl, 2 ex