Racial differences in the predictive value of the TDx fetal lung maturity assay

• Published in: American journal of obstetrics and gynecology 1996-07, Vol.175 (1), p.73-77
• Main Authors: Berman, Susan, Tanasijevic, Milenko J., Alvarez, Juan G., Ludmir, Jack, Lieberman, Ellice, Richardson, Douglas K.
• Format: Article
• Language: English
• Subjects: African Continental Ancestry Group; Biological and medical sciences; Continental Population Groups; Delivery. Postpartum. Lactation; Female; fetal lung maturity assay; Fetal Organ Maturity; fetal pulmonary maturity; Gestational Age; Gynecology. Andrology. Obstetrics; Humans; Incidence; Infant, Newborn; Lung - embryology; Male; Maternal, fetal and perinatal monitoring; Medical sciences; predictive value; Predictive Value of Tests; Racial differences; Regression Analysis; respiratory distress syndrome; Respiratory Distress Syndrome, Newborn - epidemiology; Respiratory Distress Syndrome, Newborn - ethnology; Respiratory Distress Syndrome, Newborn - physiopathology; Risk Factors
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/S0002-9378(96)70253-3

OBJECTIVE: Black newborns have lower rates of neonatal respiratory distress syndrome compared with nonblack newborns. This has been attributed to accelerated lung maturation. Previous studies have demonstrated a difference in the predictive value of the lecithin/sphingomyelin ratio, a test for lung maturity, between races. Our study examines the predictive value of the newer TDx Fetal Lung Maturity Surfactant-to-Albumin assay. STUDY DESIGN: We reviewed the records of 393 nonblack and 87 black infants delivered within 72 hours of the TDx FLM S/A assay testing. We compared the rates of neonatal respiratory distress syndrome by race, stratified by results. RESULTS: In our study population black newborns had less than one half the rate of respiratory distress syndrome compared with nonblack newborns (4.6% vs 10.4%). To adjust for possible differences in the timing of lung maturation, the results were stratified by the TDx FLM S/A assay result. Black race had a protective effect (Mantel-Haenszel weighted odds ratio 0.30, 95% confidence interval 0.06 to 0.93, p < 0.05). This significant racial difference remained when both TDx FLM S/A assay result and gestational age were controlled in a multiple logistic regression analysis. CONCLUSIONS: There are differences in the predictive value of the TDx FLM S/A assay among races. Black fetuses are less likely to have respiratory distress syndrome. The difference in rates of respiratory distress syndrome between races must be due to either a qualitative difference in the surfactant or to an anatomic difference in fetal lungs. Consideration should be given to a lower cutoff value for a mature test result in black women. (Am J Obstet Gynecol 1996;175:73-7.)