Recurrent respiratory distress syndrome in successive preterm pregnancies.

BACKGROUND: Earlier studies suggesting an increased recurrence risk of respiratory distress syndrome (RDS) among the subsequent infants of women with a previously affected infant were based on low birth weight inclusion criteria that did not differentiate between preterm and growth-retarded infants. METHODS: We therefore carried out two cohort studies of women who delivered two singleton preterm (gestational age < 37 completed weeks) infants: 1978 to 1989 at the Royal Victoria Hospital (RVH) in Montreal and 1959 to 1966 in the United States Collaborative Perinatal Project (CPP). We compared the relative risk (RR) of the development of RDS in the second infant according to the RDS status of the first. The diagnosis of RDS was based on respiratory distress of more than 24 hours' duration and a reticulogranular pattern on a chest radiograph. RESULTS: The RVH study sample comprised 284 infants born to 142 women, and the CPP sample 642 infants born to 321 mothers. In the RVH cohort the crude RR of RDS in the second sibling was 3.3 (95% confidence interval = 1.0 to 15.1) in women whose first preterm infant had RDS versus those whose first preterm infant did not have RDS. In the CPP cohort the corresponding RR was 2.5 (95% confidence interval = 0.8 to 7.9). These elevated risks were not altered substantially when multiple logistic regression was used to control for potentially confounding factors known to influence the risk of RDS (gestational age, sex, route of delivery, antenatal corticosteroids, and respiratory depression of birth). CONCLUSIONS: We conclude that preterm infants born to women with a previous preterm infant affected by RDS are at an increased risk of RDS, which suggests an important genetic (or other familial) tendency in its origin.

Hazards and benefits of elective induction of labor.

Labor, delivery, and newborn course were studied in 621 pregnancies in which labor was electively induced at or after 39 weeks, and in 3,851 control pregnancies in which the onset of labor was spontaneous. Induced labors were not prolonged, nor was the duration of ruptured membranes. Fetal distress and birth asphyxia were not more frequent after induction, and release of meconium occurred much less frequently (9.3% for induced labor versus 16.7% for spontaneous). There was greater use of epidural analgesia and of forceps delivery in induced labor. Among primiparous patients, cesarean delivery for "failure to progress" was performed in 14% of electively induced labors and 7% of spontaneous control labors, a difference not noted among multiparous patients who had a primary cesarean birth rate of less than 2%. Iatrogenic prematurity was not a problem; none of the 621 infants who was born after elective induction developed respiratory distress syndrome, and only one weighed less than 2,500 gm.