Occurrence of diabetogenic changes in pregnancy among black women in an urban setting.

OBJECTIVE To find out if pregnancy in black Zimbabwean women is a diabetogenic state using basal blood levels of cortisol, insulin, C-peptide and glucose. METHODS 111 women (28 non-pregnant, 29 first trimester, 26 second trimester and 28 third trimester) aged between 18 and 35 years were recruited for the study. Fasting plasma cortisol, insulin, C-peptide and glucose were determined by standard methods. The glucose/insulin ratio was used as an index of insulin sensitivity and the C-peptide/glucose ratio as well as the homeostasis assessment model (HOMA) as an index of insulin resistance. RESULTS The means of fasting plasma cortisol levels were significantly elevated, p < 0.0001 among the four groups (non-pregnant, first, second and third trimester women). Fasting plasma insulin levels peaked during the third trimester and significant differences were noted among all women, p < 0.05. Similar data was obtained for C-peptide levels (a better indicator of beta-cell insulin secretory activity) among the groups, p < 0.01. The means of fasting plasma glucose levels were significantly decreased with advancing gestation, p < 0.0001. Significantly lower glucose/insulin ratios, a measure of insulin sensitivity and elevated C-peptide/glucose ratios, an index of insulin resistance, were demonstrated among the women, (p < 0.05 and < 0.01 respectively). CONCLUSION The basal data presented in this paper clearly demonstrates that the diabetogenic effects of pregnancy are also expressed by Zimbabwean black women, especially in late gestation.