Changes in sleep quality during pregnancy and the postpartum period do not alter the daily pattern of cortisol levels throughout the day, but they may still affect the spike in cortisol that occurs...

The overall amount of sleep during pregnancy and the postpartum period does not predict the level of cortisol released upon waking; instead, sudden changes from a person's usual sleep pattern are more closely linked to this stress response.

In women during pregnancy and after childbirth, fluctuations in sleep quality from their own normal pattern are linked to a stronger rise in the stress hormone cortisol upon waking, with greater deviations in sleep scores corresponding to higher cortisol increases.

Women who experience sudden disruptions in sleep during pregnancy or after childbirth show higher levels of cortisol upon waking, which may be linked to complications during or after pregnancy through changes in stress hormone regulation.

During pregnancy and shortly after childbirth, the rise in cortisol levels upon waking follows an upward pattern, which contradicts earlier beliefs that this response decreases during pregnancy and returns to normal right after birth. This suggests that people differ in how their stress hormone systems behave during this time.

People who work night shifts or irregular hours tend to have weird cortisol patterns—low in the morning and high at night—which seems to make their sleep worse. This might be because their body’s internal clock is out of sync with their work schedule.