Estimation of Fetal Maturity by Amniotic Fluid Cytology, Creatinine, Lecithin/Sphingomyelin Ratio and Phosphatidylglycerol

Abstract

The value of four amniotic fluid tests – the lecithin/sphingomyelin ratio, the presence of phosphatidylglycerol, amniotic fluid cytology and the creatinine concentration – in the prediction of fetal lung maturity was investigated. The sensitivity was high for all tests except for amniotic fluid cytology, which had a higher specificity. The overall outcome, particularly the value for predicting immaturity, was improved by various combinations of tests. The combination of amniotic fluid cytology and creatinine proved useful in predicting the gestational age. A diagram for estimation of gestational age is presented.

Amniotic fluid C-peptide and phosphatidyl glycerol in diabetic pregnancy

“…It can be specudiabetes. Phosphatidyl glycerol was present in lated that a delayed disappearance of insulin 40 per cent of the diabetic pregnancies which is a receptors and an increased receptor affinity for figure that corresponds to our findings in non-insulin in the fetal lung in the offspring of diabetic diabetic pregnancies at a comparable gestational women could lead to enhanced insulin sensitivity age (36 weeks) [22] and is also similar to reports and hence, a decrease in glycogenolysis and in of other investigators [1,3]. surfactant production.…”

Biochemical profile of amniotic fluid for the assessment of fetal and renal development

“…Creatinine concentrations in amniotic fluid increased gradually between 20 to 32 weeks of gestation and more rapidly thereafter, when they were two to four times higher than in maternal serum (9,22,23). Creatinine concentrations of 2 mg/dl represent an age of at least 37 weeks of gestation (24).…”

“…Renal maturity is defined by the increase in glomerular filtration and by the maturity of renal tubular cells that begin to express various tubular transporters over the months of gestation (9,(19)(20)(21). Glomerular filtration in the fetal kidney can be assessed by the concentrations of creatinine and urea in the amniotic fluid (12).…”

“…Analysis of creatinine and urea in amniotic fluid permits an evaluation of renal maturation and functionality throughout pregnancy (6)(7)(8)(9). Creatinine values in the amniotic fluid that best represent fetal maturity are 1.5 to 2.0 mg/dl (6,10).…”

Estimation of Gestational Age by Amniocentesis

“…By using multivariate analysis we have found previously that the week of gestation can be predicted even more precisely by the use of a mathematical func tion based upon the results of both these tests. This function can be converted into a simple diagram from which paired values from the two tests can be easily read as an estimate of gestational age [6],…”