Risk factors for transient tachypnea of the newborn in infants delivered vaginally at 37 weeks or later.

In this case-control study, we examined infants delivered vaginally at 37 weeks or later to identify factors associated with transient tachypnea of the newborn (TTN). We reviewed the obstetric records of all vaginal deliveries at the Japanese Red Cross Katsushika Maternity Hospital from 2005 through 2007. Demographic information and the characteristics of labor were extracted from patient charts. Multivariate analysis identified that the incidence of TTN was significantly associated with nulliparity; a history of infertility therapy, such as in vitro fertilization; augmentation of labor; nonreassuring fetal status; vacuum/forceps delivery; and low Apgar score (<7) at 1 and 5 minutes. In addition, a low Apgar score at 1 minute was the factor most strongly associated with the incidence of TTN (adjusted odds ratio, 20; 95% confidence intervals, 12-34; p<0.001). The present results indicate that the improvement of obstetric surveillance to diminish the frequency of low Apgar scores is important for preventing TTN in infants delivered vaginally at 37 weeks or later.