Gestational diabetes in a developing country, experience of screening at the Aga Khan University Medical Centre, Karachi.

In order to determine the prevalence of glucose intolerance in pregnancy, 1267 consecutive women attending the antenatal clinic of the Aga Khan University Medical Centre were subjected to a 75 g glucose challenge followed 2 hr later by plasma glucose determination irrespective of gestation on the first antenatal visit. The test was repeated at 28-32 weeks of gestation if the patients had an abnormal initial screen at less than 28 weeks gestation and a normal glucose tolerance test on diagnostic follow-up and for those who had a risk factor for gestational diabetes and a normal initial screen at less than 28 weeks gestation. The glucose challenge test was abnormal (2 hr plasma glucose greater than 140 mg%) in 8.6% of the screened population. Follow-up oral glucose tolerance test on these patients revealed a prevalence of 3.2% of gestational diabetes and 1.9% of impaired glucose tolerance test based on the modified O'Sullivan criteria. Improvement in cost effectiveness of screening programmes was adjudged possible by avoiding glucose tolerance tests in patients with 2 hr plasma glucose value of greater than 170 mg% after a 75 g oral glucose challenge for screening.