Progesterone concentration rises to a peak near term, and this hormone is responsible for many of the changes described in this session. The fall in concentration just before term may be a factor leading to the initiation of normal labour.

Human chorionic gonadotrophin (hCG) is the hormone which pregnancy tests are designed to measure.

Human placental lactogen (hPL) (also known as chorionic somatomammotrophin) is a peptide hormone with a structure and function similar to that of growth hormone. It causes impaired glucose tolerance due to insulin resistance.

A rise in maternal basal metabolic rate (contributing to increased oxygen consumption) occurs.

Increased aldosterone secretion from the adrenal cortex results in Na⁺ and water retention.