Incidence of gestational diabetes at Northdale Hospital, Pietermaritzburg.

An incidence study for gestational diabetes was undertaken at Northdale Hospital, which serves a majority Indian and minority Coloured population in Pietermaritzburg. All patients presenting to the antenatal clinic were screened using a 75 g glucose load. If the 1-hour venous plasma glucose level was greater than or equal to 7.8 mmol/l an oral glucose tolerance test (OGTT) was performed. The screening procedure was repeated at 28 - 32 weeks gestation. The OGTT was done with a 75 g glucose load and patients were designated as having gestational diabetes if the 2-hour plasma glucose level was greater than or equal to 7.8 mmol/l. Subsequently, the patients were also evaluated by the 3rd trimester criteria of the Diabetes Pregnancy Study Group of the European Association for the Study of Diabetes (EASD): gestational diabetes being present if the fasting plasma glucose value was greater than or equal to 5.2 mmol/l and the 2-hour plasma glucose value was greater than or equal to 9.0 mmol/l after a 75 g glucose load. Between July 1987 and June 1988 1721 patients were seen. There were 4 pre-gestational diabetics. The remaining 1717 patients were screened for gestational diabetes. Forty-five patients had 2 OGTTs performed, while 251 patients had 1 OGTT in the 3rd trimester. Sixty-five patients had a 2-hour plasma glucose value of greater than or equal to 7.8 mmol/l on OGTT. Hence, the incidence of gestational diabetes using World Health Organisation criteria was 65/1717 (3.8%). Twenty-seven patients had 2-hour plasma glucose value of greater than or equal to 9 mmol/l on OGTT.(ABSTRACT TRUNCATED AT 250 WORDS)