Non-fasting OGTT versus Fasting OGTT for screening of Hyperglycaemia in Pregnancy (HIP)

To compare the reliability of non-fasting oral glucose tolerance test (OGTT) versus fasting OGTT for screening of hyperglycaemia in pregnancy (HIP).

This cross sectional analytic study was conducted by the Department of Obstetrics & Gynaecology, Isra University Karachi Campus from October 2016 to April 2017. A total of 225 pregnant women irrespective of gestational age were included in the study. They underwent non fasting 75 grams OGTT. Venous plasma glucose was done 02 hours after the glucose load. Same women were advised to come again within three to seven days for fasting OGTT. Venous plasma glucose (VPG) was estimated in fasting and 2 hours post glucose load.

Using the non-fasting OGTT, out of 204 women, 32 were diagnosed with hyperglycemia. All these 204 women were again called for fasting OGTT three to seven days after the initial non-fasting OGTT. Only nine were diagnosed with hyperglycemia, out of these nine women, seven women who were screen positive on non-fasting OGTT were found to be screen positive on fasting OGTT as well. However, only two women were additionally diagnosed with hyperglycemia who were initially screen negative on non-fasting OGTT. The non-fasting OGTT has diagnosed HIP with sensitivity of 77.7%, specificity of 87.1%, positive predictive value of 21.8% and negative predictive value of 98.8%.

The use of the non-fasting OGTT at first antenatal visit may be a practical approach to detect the HIP as screening and diagnostic tool in the resource constrained settings.