Laurence E. Stempel

Assessment of a rapid test on amniotic fluid for estimating fetal lung maturity

We have measured the absorbance of centrifuged amniotic fluids at 650 nm. and found reasonably good correlation between the absorbance and the L/S ratio. In 87 fluids studied, an absorbance of greater than 0.100 predicted correctly an L/S ratio of 2 or more in 98 per cent of the cases. When the absorbance was less than 0.100, 70 per cent of the fluids had an L/S ratio of less than 2.

Capillary gas chromatographic—mass spectrometric profiles of trimethylsilyl derivatives of organic acids from amniotic fluids of different gestational age

Amniotic fluid from different gestational age patients was partitioned into neutral, acidic and basic fractions. The organic acids were trimethylsilylated and analyzed by glass capillary gas chromatography-mass spectrometry. A marked difference in the level of hippuric acid was observed between samples from early (15-22 weeks) and late (30-38.5 weeks) pregnancy. This difference probably reflects the degree of maturity in the fetal liver and kidney. The procedures establish amniotic fluid profiles of substances of varying gestational age and should be useful in determining alterations caused by diseases.

Diagnosis of fetal death in utero with amniotic fluid creatine kinase.

There is a need for a widely available and accurate method of diagnosing fetal death in utero. The accepted standard technique for making this diagnosis is real-time ultrasonography, but this procedure is not available at all hospitals. However, almost every hospital laboratory has the capability of measuring creatine kinase in body fluids. One hundred eight pregnant women underwent real-time ultrasonography and analysis of amniotic fluid for creatine kinase. Ninety-one women with conditions that required amniocentesis during the second and third trimesters had a life fetus by ultrasonographic examination and a low level of amniotic fluid creatine kinase (0 to 3 sigma units per milliliter). Seventeen women with a dead fetus by ultrasonographic examination had an abnormally high level of amniotic fluid creatine kinase (5 to 9,800 sigma units per milliliter). The only erroneous diagnosis in this series involved a set of twins, one of whom was shown by real-time ultrasonography to be alive and the other dead. Both sacs contained abnormally high, although different, levels of creatine kinase. Analysis of creatine kinase in amniotic fluid is a reliable technique for diagnosing fetal death.