SAN FRANCISCO — Newborns with a 5-minute Apgar score of 7 or less have a high risk of developing respiratory distress syndrome, according to Linda R. Chambliss, M.D., associate director of maternal fetal medicine at the Maricopa Integrated Health System in Phoenix, Ariz.
The recent findings should help alert physicians to high-risk infants who should be monitored more intensively or given therapies to reduce the incidence or severity of respiratory distress syndrome (RDS), she reported at the annual meeting of the American College of Obstetricians and Gynecologists.
“What is surprising is that many people, including myself, have felt that as long as the 5-minute Apgar hits 7, the baby will be fine, but this is not necessarily the case,” she told this newspaper. “Clinicians who deliver an infant with such a score should counsel the families and the nursery that RDS is very likely. These infants have to be watched very closely.”
Her study analyzed more than 26,000 births from a statewide registry and identified 657 admissions to neonatal intensive care with a diagnosis of RDS.
Of these admissions, 540 infants had an Apgar score of 7 or less, compared with 3,803 infants who had the same Apgar score but no RDS.
After controlling for education level, marital status, race, parity, smoking, prenatal care, diabetes, hypertension, preeclampsia, induction/augmentation of labor, intrapartum fever, prolonged rupture of membranes, abruption, nonreassuring fetal heart rate, delivery by cesarean, infant's gender and gestational age, the 5-minute Apgar score of 7 or less was an independent risk factor for RDS, with an adjusted odds ratio of 25, Dr. Chambliss said.
When the infant's birth weight was substituted for gestational age, the risk remained similar (odds ratio 22).
Low birth weight and prematurity are well-recognized risk factors for the development of RDS, even when Apgar scores are normal, Dr. Chambliss said.
But her findings suggest that regardless of birth weight or prematurity, or any of the other variables that the researcher measured, the 5-minute Apgar score of 7 or less remains a high risk factor for RDS.
“People may not have realized how strongly this predicts future problems with RDS. While the Apgar score may not be the best way to predict some complications, such as neurological injury, we feel it has a great deal of utility to predict the risk RDS even when controlled for a number of other variables,” she said.