The use of ultrasound measurement of fetal lung length to predict neonatal respiratory outcome after prolonged premature rupture of the membranes.
OBJECTIVE
The purpose of this study was to investigate the use of fetal lung length estimation by ultrasound in the prediction of adverse neonatal respiratory outcome after prolonged preterm rupture of the membranes.


METHODS
From the hospital database of all cases of spontaneous membrane rupture </=28 weeks' gestation, normal singleton pregnancies with membrane rupture for at least 7 days and delivery after 24 weeks' gestation where lung length measurements were available were studied. The study period was 5 years. At least one lung length measurement >/=7 days after membrane rupture needed to be available and the last lung length prior to delivery was used to predict adverse respiratory outcome. Complete neonatal follow-up was available on all babies. Neonatal outcome measures included survival, bronchopulmonary dysplasia defined as an oxygen requirement at 36 weeks' gestation, and neonatal respiratory death in non-survivors. Two groups, good and poor outcomes, were defined. A comparison of the last lung length before delivery (corrected for gestation) between the good and poor outcome groups was made to determine whether lung length could predict neonatal outcome.


RESULTS
There were 43 live births. All had received antenatal corticosteroids as part of the management of prematurity. There were no differences in maternal age, ethnicity, parity and the incidence of antepartum haemorrhage between the good and poor outcome groups. Parameters significantly associated with good outcome included gestation at membrane rupture, large pool of amniotic fluid and gestation at delivery. The last fetal lung length did not predict adverse neonatal respiratory outcome. In the 28 babies where membrane rupture was >/=21 days the findings were the same.


CONCLUSIONS
Fetal lung length determined by antenatal ultrasound does not predict adverse neonatal respiratory outcome and the prediction of pulmonary hypoplasia in live borns after prolonged preterm rupture of the membranes remains an elusive goal.
Stone
Peter
P
Department of Obstetrics and Gynaecology, University of Auckland, National Women's Hospital, Auckland, New Zealand. p.stone@auckland.ac.nz
Grant
Steven
S
Sadler
Lynn
L
Battin
Malcolm
M
Mitchell
Jenny
J
D000305:Adrenal Cortex Hormones / Q000008:administration & dosage; D000328:Adult; D001997:Bronchopulmonary Dysplasia / Q000453:epidemiology; D005260:Female; D005322:Premature Rupture of Fetal Membranes; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D008168:Lung / Q000000981:diagnostic imaging* / Q000196:embryology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D012140:Respiratory Tract Diseases / Q000000981:diagnostic imaging*; D013997:Time Factors; D016216:Ultrasonography, Prenatal
D000305:Adrenal Cortex Hormones