Ontogeny of surfactant proteins A and B in human amniotic fluid as indices of fetal lung maturity.
Surfactant proteins A and B (SP-A and SP-B) were measured in human amniotic fluid by ELISA and correlated with lecithin to sphingomyelin ratio (L/S), phosphatidylglycerol (PG), and perinatal outcome. Amniotic fluid SP-A, SP-B, and L/S increased with advancing gestation. SP-A was detected at 19 wk gestation and increased dramatically in the 3rd trimester of pregnancy. SP-B was first detectable at 31 wk gestation and increased significantly to term. SP-A was a more specific predictor of nonrespiratory distress syndrome (RDS) than L/S or SP-B; however, the sensitivity of SP-A in predicting RDS was less than L/S less than 2.0 (26.3 versus 82.3%, respectively). In 209 pregnancies assessed within 48 h of delivery, the sensitivity of SP-B in predicting RDS (nondetectable SP-B) was comparable to the L/S, however, SP-B = 0 was frequently observed in mature infants, limiting its specificity for prediction of RDS. The greatest sensitivity and specificity were achieved with the measurement of L/S less than 2.0 and negative PG, which correctly predicted 100% of the infants with RDS and 94% of those who did not develop the disorder. Measurement of SP-A or SP-B did not improve the prediction of RDS. SP-A, SP-B, and L/S were not affected by infant sex, Apgar score, rupture of membranes, size for gestational age, maternal diabetes, hypertension, or exposure to medications. SP-A, SP-B, and L/S were significantly elevated in amniotic fluid from black mothers. SP-A was significantly elevated in amniotic fluid from mothers who smoked during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)
Pryhuber
G S
GS
Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio 45229-2899.
Hull
W M
WM
Fink
I
I
McMahan
M J
MJ
Whitsett
J A
JA
D000653:Amniotic Fluid / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005325:Fetal Organ Maturity / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology* / Q000378:metabolism*; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis; D011510:Proteolipids / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis
D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants