This type of diabetes develops when the hormones produced by the placenta to help the baby grow, interefere with the mode of operation of insulin to regulate blood glucose levels. This is referred to as insulin resistance. As a result, the level of glucose in the blood stream increases. The diagnostic tests are carried out, mainly around mid-way through with the pregnancy that is 24 - 28 weeks. This test is called the oral glucose tolerance test (OGTT). 

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