title: The pattern of change in the lecithin/sphingomyelin ratio in patients with preterm premature rupture of membranes between 24 and 34 weeks' gestation.
abstract: OBJECTIVE
  To report the pattern of change in the lecithin/sphingomyelin (L/S) ratio in patients with preterm premature rupture of membranes (PPROM) between 24 and 34 weeks' gestation.
  
  
  METHODS
  L/S was determined prospectively using transvaginally and transabdominally collected amniotic fluid from patients with PPROM between 24 and 34 weeks' gestation. Samples were collected prospectively on admission and every 48 to 96 hours until L/S was > or =2.0. All patients received intramuscular betamethasone weekly.
  
  
  RESULTS
  Fifty-five patients were included in the study. One hundred twenty-seven samples were collected transvaginally and nine were collected transabdominally. Cox regression analysis showed that a higher initial L/S value and more advanced gestational age were associated with accelerated lung maturation. Among patients at > or =29 weeks' gestation with an initial L/S of > or =1.5 and <2.0 (n=17), 15 of 17 (88%) reached L/S > or = 2 at a mean of 3.1 +/- 1.7 days (range 1.0 to 7.0 days). With an initial L/S of > or =1.0 and <1.5 (n=16), 14 of 16 (88%) patients reached L/S > or =2 at a mean of 4.1 +/- 1.9 days (range 1.7 to 7.0 days). With an initial L/S of <1.0 (n=11), 6 of 11 (54%) patients reached L/S > or =2 at a mean of 5.0 +/- 1.6 days (range 4.7 to 6.8 days).
  
  
  CONCLUSIONS
  Our data document a dramatic acceleration of fetal lung maturation among patients with PPROM at > or = 29 weeks.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, University of Louisville, Louisville, KY, USA.
authors.forename: Helen Y
authors.initials: HY
authors.lastname: How
authors.forename: Curtis R
authors.initials: CR
authors.lastname: Cook
authors.forename: Vernon D
authors.initials: VD
authors.lastname: Cook
authors.forename: Kathleen K
authors.initials: KK
authors.lastname: Ralston
authors.forename: Eileen R
authors.initials: ER
authors.lastname: Greenwell
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Goldsmith
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Spinnato
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry*; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000175:diagnosis*; D005325:Fetal Organ Maturity; D006801:Humans; D008297:Male; D010713:Phosphatidylcholines / Q000032:analysis*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D012727:Sex Characteristics; D013109:Sphingomyelins / Q000032:analysis*
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins