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Clinical problem of preterm labor.

Foreword Preterm delivery with its associated morbidity and mortality still represents one of the major unsolved problems in obstetrics and gynecology. The causes of preterm delivery may be broadly divided into three groups. These are: indicated preterm deliveries, premature rupture of membranes in the preterm gestation, and preterm labor. Indicated preterm deliveries are usually the result of various medical or surgical complications in the mother or fetus that create an unfavorable intrauterine environment for the fetus or a dangerous environment for the mother. In these cases, the fetus is delivered to prevent morbidity or mortality of mother or fetus from occurring regardless of gestational age. These conditions commonly include severe preeclampsia, chronic hypertension, diabetes, placenta previa, or placental abruption. Indicated preterm deliveries often account for 20–30% of all preterm births. They therefore account for a significant proportion of the mortality and morbidity with preterm births. To decrease the occurrence of preterm deliveries in this population, advances must be made in the management of the medical condition that creates the dangerous environment for mother and fetus. The remaining 70–80% of preterm deliveries are caused by preterm premature rupture of the membranes or by preterm labor. These two conditions, although usually considered separate, are probably more closely associated than we often realize. It is quite common for preterm labor to result in rupture of the membranes and most patients with rupture of the membranes proceed quickly to preterm labor. It is likely that common mechanisms initiate one or both of these complications in any specific pregnancy. Obviously, preterm deliveries present a problem because of the severe neonatal complications that often occur afterwards. These complications are worse for the smaller newborn with earlier gestational age. These complications include death, respiratory distress syndrome, intraventricular hemorrhage, sepsis, and necrotizing enterocolitis. During the past 20 to 30 years, there has been a significant improvement in the survival rate of CLINICAL OBSTETRICS AND GYNECOLOGY Volume 43, Number 4, pp 713–716 © 2000, Lippincott Williams & Wilkins, Inc.