Purpose: To evaluate the correlation between maternal hyperglycemia in early pregnancy and the risk of fetal abnormalities in pregnant women with type 1 diabetes mellitus.
Study design: A retrospective study over 124 pregnant women with diabetes mellitus type 1 hospitalized in High Risk Pregnancy Department--SHATOG "Maichin dom" has been done from January. 1998 to January 2004. The diabetic pregnant women were divided in two groups: first group pregnant women without malformations n = 105 and second group pregnant women with malformations n = 19. The pregnant women with fetal malformations were divided into two subgroups: with major malformations n = 13 and with minor malformations n = 6. The diabetic pregnant women were divided in classes according to Whites Classification: Class B - 38, Class C - 35; Class D - 39 and Class R/F - 12. The values of preprandial glucose, postprandial glucose and glycosilated hemoglobin has been measured at 13 week of gestation.
Results: 104 pregnancies of total 124 pregnancies were without abnormalities. The fetal malformations were observed in 19 (15.3%) of total 124 pregnancies. The rate of major abnormalities were - 13 (10.4%) and minor abnormalities were - 7 (5.6%). The highest rate of abnormalities there has been within the complicated diabetic women of class D - n = 7 (17.9 %) and class R/F n = 3 (25%). The initial values of preprandial glucose 9.54 (SD +/- 3.59) mmol/l and postprandiai glucose 10.52 (SD +/- 1.81) mmol/l between the women whit pregnancies with abnormalities were significantly higher then those values of preprandial glucose 7.39 (SD +/- 2.82) mmol/l (P - 0.021) and values of postprandial glucose 10.52 (SD +/- 1.81) mmol/l (P = 0.014) between the women without fetal malformations. The mean values of glycosilated hemoglobin were significantly higher HbA 1 c = 9. 01% (SD +/- 1.53) in pregnancies complicated with malformations than those values measured in pregnancies without fetal malformations 8.06% (SD +/- 1.64, P = 0.022). A positive correlation between the observed abnormalities and metabolic control in the early pregnancy exist. The values of Hbeta A1-c is significantly higher Hbeta A1-c - 9.9% (SD +/- 1.2) in pregnancies complicated with fetal malformations than those measured in pregnancies without malformations. Hbeta A1-c 8.2% (SD +/- 1.5) n = 125. Significant differences in the value of Hbeta A1-c between pregnancies with mild and those with severe abnormalities have not been established. A correlation between the levels of Hbeta A1-c in early pregnancy and the rate of the observed abnormalities exist. Within the values of Hbeta A1-c < 7.9%, the rate of malformations is 6.9%, Hbeta A1-c > 8.0% < 10%, the rate of malformations is 19.0% and within the values of Hbeta A1-c > 10%, the rate of the observed abnormalities is 31.5%. A logistic regression between the higher values of postprandial glucose and Hbeta A1-c values and the relative risk of congenital malformations has been observed. The relative risk is evaluated by odds ratio (OR) When the levels of Hbeta A1-c rise with 1% the relative risk of congenital malformations is evaluated by odds ratio OR = 2.02 (limited in 1.46 - 2.81 by 95% conf. interval) and when the levels of postprandial glucose rise with 1 mmol/l the relative risk OR = 1.21 (limited in 1.06 - 1.37: 95% conf. interval).
Conclusion: Fetal abnormalities are more frequent in pregnant women with long lasting diabetes complicated with vasculopathy. Fetal abnormalities are associated with higher levels of Hbeta A1-c in the first trimester of pregnancy. In diabetic women who planed their pregnancy an optimal metabolic control must been established.