The clinical value of amniotic fluid analysis in pregnancies complicated by Rh-isoimmunization or hepatosis.

Abstract

605 samples of amniotic fluid were obtained by abdominal amniocentesis in 363 late pregnancies. The liquor was analysed with respect to ΔE450 (the optical density at 450 nm), progesterone and total protein content. On 172 samples measurements of the acid and alkaline phosphatase activity were also performed. Most of the samples came from pregnancies complicated by isoimmunization, but the material also contained samples from women with hepatosis gravidarum or other complications as well as from normal pregnancies. The measurements have been studied in relation to duration of pregnancy, cord blood haemoglobin levels, cord serum bilirubin levels, infant birth weight, maternal serum bilirubin levels, maternal alkaline phosphatase levels, maternal age, order of pregnancy, maternal and infant blood groups. For part of the series the relationships between the parameters were studied by multiple regression analysis. The results indicate a rather weak correlation between infant cord blood haemoglobin levels and the other parameters. The ABO blood groups of mother and infant influence the levels of cord blood haemoglobin, cord serum bilirubin and amniotic fluid total protein. Amniotic fluid progesterone and ΔE450 values are correlated to amniotic fluid total protein levels. Low ΔE450 values indicate that the fetus is mature. Determinations of ΔLE460 before the 37th week show a better correlation with the condition of the infant than later ones. Order of pregnancy influences the total protein content of amniotic fluid in normal pregnancies. Determinations of acid and alkaline phosphatases in amniotic fluid do not give any clinically important information in cases of isoimmunization. Meconium contamination strongly increases alkaline phosphatase activity. Attempts to use the rapid method of Brown for oestrogen determinations in amniotic fluid proved to be difficult for technical reasons.