What is the best time and precautions for pregnant women to measure blood glucose?

The optimal time for pregnant women to test blood glucose is between 24 and 28 weeks of gestation, with testing options including early morning fasting, before meals, and 1–2 hours after meals. Key considerations include selecting the correct testing time and appropriate frequency of glucose monitoring. The details are as follows:

1. Optimal Timing

During pregnancy, if assessing for diabetes, it is recommended to undergo an oral glucose tolerance test (OGTT) at 24–28 weeks of gestation, as maternal physiological conditions during this period provide higher test accuracy. Venous blood sampling is commonly used. Blood glucose levels are measured while fasting in the morning, and then again at 0.5 hour, 1 hour, and 2 hours after ingesting 75 grams of glucose. The normal fasting blood glucose range is 3.1–5.1 mmol/L; the normal 1-hour postprandial glucose level is less than 10.0 mmol/L; and the normal 2-hour postprandial glucose level is less than 8.5 mmol/L. If fasting glucose exceeds 5.1 mmol/L, 1-hour postprandial glucose exceeds 10.0 mmol/L, or 2-hour postprandial glucose exceeds 8.5 mmol/L, gestational diabetes may be present.

2. Precautions

1) Correct Testing Time

When measuring blood glucose, it is important to choose the appropriate testing time to avoid inaccurate results due to improper timing, which could affect diagnosis.

2) Appropriate Testing Frequency

After conception, fasting blood glucose and 2-hour postprandial glucose after each of the three daily meals should be measured once weekly. For those requiring insulin therapy, blood glucose should be monitored before and after each meal daily.

If abnormal glucose levels are detected, the underlying cause should be promptly identified and appropriate treatment initiated accordingly.