Background: Clinical studies suggest that respiratory outcome of infants born preterm may be influenced by placental insufficiency and hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome. If so, one could expect to see differences in lung maturation indices (lecithin/sphingomyelin (L/S) ratio and lamellar body count (LBC)) in the amniotic fluid. The present study investigates lung maturation indices of preterm small for gestational age (SGA) fetuses with or without abnormal Doppler ultrasound examination and with or without maternal hypertension/HELLP syndrome.
Study design: Retrospective cohort study of 76 neonates born in our center between 1997 and 2003 with gestational age (GA) <34 weeks, birth weight <p10 for GA and available results from amniocentesis. All analyses were corrected for potential confounders.
Results: The L/S ratio was significantly higher in the abnormal Doppler group as compared to the normal Doppler group (p=0.02). The L/S ratio was significantly lower in hypertensive pregnancies as compared to normotensive pregnancies (p=0.02). Subdivision of the maternal hypertension group showed a significantly lower L/S ratio in the HELLP syndrome group as compared to the normotension group (p=0.04).
Conclusion: The L/S ratio of SGA fetuses is significantly higher in cases with presumed placental insufficiency and significantly lower when pregnancies are complicated by HELLP syndrome. These observations are in line with the hypothesis that placental insufficiency accelerates lung maturation and with recent reports of poorer respiratory outcome in infants from mothers with HELLP syndrome.