29th June 2023

Endocrinology and glycaemic control

There is an increase in peripheral insulin resistance and a subsequent increase in insulin production during normal pregnancy. Fasting glucose levels, therefore, fall with increased postprandial levels. Starvation, particularly in the third trimester, carries with it an increased risk of ketoacidosis.

Both pituitary and adrenal hormone levels are altered significantly. As well as the expected fall in FSH and LH due to the high progesterone and oestrogen levels, there is a slow increase in prolactin as pregnancy progresses.

The placenta secretes a number of hormones which are similar in structure to pituitary hormones. Placental hormones include growth hormone, cortisol releasing hormone and vasopressinase.

There is an increase in thyroid binding globulin resulting in an increase in T4 production and iodine requirements.

Renin and aldosterone levels are also significantly increased.