Objectives

To determine the validity of fasting blood glucose as the only value to perform the diagnosis of gestational diabetes in the first trimester of pregnancy, according to the criteria of the IADPSG. To calculate the sensitivity, specificity, positive and negative predictive value of this test comparing it with the gold standard "Oral glucose tolerance test".

Materials and methods

Case-control retrospective study carried out from 2014 to 2017. In the case group, patients diagnosed with gestational diabetes were included in the week 24 to 28 of pregnancy through an oral glucose tolerance test. Fasting blood glucose was recorded in the first trimester of pregnancy. A random sampling was done to obtain the control group with the result of the negative test. Statistical analysis was performed with SPSS Statistics. For the valid ity of the test, sensitivity, specificity, PPV, NPV, positive and negative likelihood ratio were calculated.

Results

In the case group, 204 patients were obtained, 68.1% with fasting blood glucose ≥ 92 mg/dL and 31.9% with normal glucose values in the first trimester of pregnancy. 50% of overweight patients and 100% of patients with obesity had glycemia ≥ 92 mg/dL. In the control group of 204 patients, only 5.3% had values ≥ 92 mg/dL. The OR for the development of gestational diabetes with this glucose value in the first trimester was 37.5 95%CI: 19.1-73.7. The sensitivity of the test was 68%, specificity 95%.

Conclusions

The fasting glucose value as the only diagnostic test of gestational diabetes during the first trimester has an acceptable sensitivity and a good specificity especially in patients with overweight or obesity.

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