Breech presentation and fetal growth retardation.

Although it has been consistently demonstrated that breech presentation is associated with fetal growth retardation, this relationship has not been clarified. This study intends to elucidate this association by use of live births recorded in North Carolina in 1988 and 1989. A remarkable difference in birth weight between breech and vertex infants existed only in the preterm births. Although the breech infants had a higher proportion of small for gestational age than the vertex infants, the difference in the proportions decreased with advancing gestational age. Our analysis indicated that breech presentation is unlikely to be a cause of fetal growth retardation. Results of the study also implied that the significant association between breech presentation and increased perinatal mortality may be due in part to the common correlation with premature delivery and fetal growth retardation.