What hormonal change occurs during pregnancy that can lead to increased blood glucose levels in the mother?

During pregnancy, the increase in human placental lactogen (HPL) is significant in relation to maternal blood glucose levels. HPL, which is produced by the placenta, plays a critical role in ensuring the developing fetus receives adequate nutrients. It acts as an insulin antagonist, meaning it reduces the effectiveness of insulin. This action leads to insulin resistance in the mother, allowing more glucose to remain in the bloodstream. As a result, maternal blood glucose levels can rise, providing a constant supply of glucose to the fetus.

Understanding the role of HPL is essential for managing blood sugar levels during pregnancy, especially in the context of gestational diabetes. The other hormonal changes, while they do impact pregnancy in various ways, do not primarily contribute to the increase in maternal blood glucose levels in the same direct manner as HPL.