Amniotic fluid phosphatidylglycerol and prediction of fetal lung maturity in diabetic pregnancies

Surfactant abnormality and the sudden infant death syndrome--a primary or secondary phenomenon?

A prospective study of 46 infant deaths occurring between 3 and 100 weeks of age was performed and comprised a structured necropsy followed by collection of lung washings for surfactant phospholipid analysis and samples for microbiological examination. Of the 46 infants studied, 23 died from sudden infant death syndrome (SIDS) alone; SIDS was the cause of death in a further 12 but there were additional clinical or pathological findings insufficient in themselves to account for the death ('SIDS-plus'). In 11 there were other causes of death ('non-SIDS'). The lung washings from infants dying from SIDS had significantly lower concentrations of phosphatidylcholine and a significantly lower palmitate content in the phosphatidylcholine. There was no association between surfactant phospholipid abnormality and the presence of recognised pathogens, histological evidence of pulmonary inflammation, aspiration of stomach contents, age at death, sex, and death-postmortem interval. There were, however, lower concentrations of phosphatidylcholine and phosphatidylcholine palmitate content in infants colonised by organisms with reported phospholipase A2 activity.

Human amniotic fluid urogastrone (epidermal growth factor) and fetal lung phospholipids

Urogastrone was measured by radioimmunoassay in amniotic fluid obtained from 186 complicated pregnancies at 22 to 40 weeks gestation. Amniocentesis was performed for a variety of indications to obtain information about fetal lung maturity or bilirubin levels before induction of labour or caesarean section in various obstetric conditions. In 114 specimens lung phospholipids extracted from amniotic fluid were also assayed using two-dimensional thin layer chromatography. Urogastrone concentrations became measurable at approximately 30 weeks gestation and thereafter there was a 10-fold rise in concentrations between 30 and 40 weeks gestation. This increase in urogastrone concentration was positively correlated with a rise in phosphatidylcholine and phosphatidylglycerol concentrations and the phosphatidylcholine (lecithin)/sphingomyelin ratio (L/S). These results are compatible with a role for urogastrone in human fetal lung maturation.

Maternal diabetes and neonatal respiratory distress. I. Maturation of fetal surfactant

The phospholipid composition of amniotic fluid samples from 30 normal patients and 44 diabetic patients over the last 10 weeks of pregnancy was studied. Higher levels of phosphatidylcholine (PC) and phosphatidylinositol (PI) were found in diabetic pregnancies where there was excellent glucose control. These differences were statistically significant at 34-36 weeks. Phosphatidylglycerol (PG) appeared significantly earlier in the well controlled diabetic pregnancies, but even in the poorly controlled diabetics the levels of PC, PI and PG were comparable to those in normal pregnancies. There was no evidence of delayed appearance of fetal surfactant phospholipids in either the well or poorly controlled diabetic pregnancies. The absolute lecithin (PC)/sphingomyelin (SM) ratio in diabetic pregnancies was generally greater for any given gestational age than those in normal pregnancies. Whilst in most cases this was due to a higher PC concentration, in a few poorly controlled diabetics it was the result of a lower concentration of SM.