AMNIOTIC-FLUID INSULIN LEVELS IN NONDIABETIC PREGNANT-WOMEN - AN UPDATE

Elevated amniotic fluid insulin levels in diabetes are frequently desc ribed but there are few systematic data on metabolically healthy women to define normal ranges. Previous studies had too high normal ranges because they were based on unspecific insulin binding radioimmunoassay s. The aim of the study was to update normal amniotic fluid insulin da ta and to define a reliable normal range in the course of a nondiabeti c pregnancy. Amniotic fluid insulin levels were measured in 841 amniot ic fluid samples of 707 nondiabetic women undergoing amniocentesis for hydramnios, suspected malformation, determination of lung maturation, Rhesus antibodies and cordocentesis. Mean (+/-SD) of amniotic fluid i nsulin level was 3.6 (+/-2.1) mu U/mL at 31.5 (+/-4.9) weeks of pregna ncy. The 97th percentile was 8.2 mu U/mL. Insulin levels show a biphas ic course between 16th and 42nd weeks of pregnancy with a zenith at 30 th week. Only two cases (0.3%) had unexplicably elevated amniotic flui d insulin levels greater than or equal to 10 mu U/mL. Thus, in nondiab etic women amniotic fluid insulin levels >10 mu U/mL are unlikely.