LEVELS OF AMNIOTIC-FLUID INSULIN AND PROFILES OF MATERNAL BLOOD-GLUCOSE IN PREGNANT-WOMEN WITH DIABETES TYPE-I

The aim of this study was to investigate the relationship between amni otic fluid insulin (AF-insulin) measurements and maternal blood glucos e levels in pregnancies complicated by insulin-dependent maternal diab etes mellitus (IDDM). Twenty-five patients with IDDM underwent amnioce ntesis (AC) in the third trimester. Twelve patients had a second amnio centesis after 2-3 weeks. The maternal blood glucose values (MBG) 2 we eks before amniocentesis were correlated with AF-insulin. Mean (+/-S.D .) MBG in the group with AF-insulin > 97th centile (n = 7) was 6.1+/-1 mmol/l. MBG in the group with AF-insulin < 97th centile (n = 18) was 5.3+/-1.2 mmol/l (r = 0.2948; P-value 0.162). In the group with repeat ed AC and AF-insulin > 97th centile (n = 6) the correlation coefficien t was 0.722 (P = 0.043), whereas in the group with normal AF-insulin ( n = 6) no correlation was found (r = - 0.213; P = 0.686). These result s indicate that no significant correlation exists between MBG values a nd concentration of AF-insulin. MBG is not appropriate for the diagnos is of fetal hyperinsulinism in well-controlled women with IDDM. In ind ividual cases with AF-insulin > 97th centile a decrease of MBG causes lower AF-insulin levels. These results indicate that there seems to be an individual threshold for maternal MBG which causes hyperinsulinism . Fetal hyperinsulinism not only depends on blood glucose levels. Diff erent fetal sensitivity to maternal glucose stimuli or a different glu cose transport across the placenta in the individual fetus could be re sponsible for these results. (C) 1997 Elsevier Science Ireland Ltd.