title: A normative study of obstetric complications associated with fetal trisomy 18.
abstract: Our objective was to determine whether the cesarean section rate and amniotic fluid lecithin-sphingomyelin ratio (L/S ratio) associated with fetal trisomy 18 are different from those associated with euploid pregnancies. Forty-nine trisomy 18 pregnancies were identified and their records were reviewed. Of the 22 live-born infants, 15 (68%) were delivered by cesarean section. The overall cesarean section rate for the institution ranged from 19.1% to 22.6%. In five patients with gestational ages between 35 and 38 weeks who had amniocentesis as part of the evaluation of intrauterine growth retardation, the L/S ratios were < or = 1.8. These data confirm that undiagnosed trisomy 18 pregnancies are associated with an increased cesarean section rate. Further, trisomy 18 fetuses appear to have delayed maturation of the L/S ratio. These results reinforce the importance of a karyotypic evaluation of selected pregnancies complicated by intrauterine growth retardation, even in the third trimester, and suggest that the prenatal diagnosis of trisomy 18 is of obstetric importance.
authors.affiliation: Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, R.I., USA.
authors.forename: D N
authors.initials: DN
authors.lastname: Saller
authors.forename: C E
authors.initials: CE
authors.lastname: Oyer
authors.forename: J
authors.initials: J
authors.lastname: Star
authors.forename: J A
authors.initials: JA
authors.lastname: Canick
mesh_terms: D000649:Amniocentesis; D000653:Amniotic Fluid / Q000378:metabolism; D002585:Cesarean Section / Q000706:statistics & numerical data; D002887:Chromosomes, Human, Pair 18; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D005317:Fetal Growth Retardation; D006801:Humans; D010713:Phosphatidylcholines / Q000378:metabolism; D011247:Pregnancy; D011248:Pregnancy Complications / Q000517:prevention & control*; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D011296:Prenatal Diagnosis / Q000379:methods; D013109:Sphingomyelins / Q000378:metabolism; D014314:Trisomy / Q000175:diagnosis*
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins