The menstrual cycle can change dates every month due to various reasons. According to, some of the potential causes of changes in period dates include:

• Stress: Chronic amounts of stress can affect the length of the menstrual cycle, leading to a change in period dates. Stress releases cortisol, the stress hormone that could interact with the hormones responsible for the different phases of the menstrual cycle, causing it to stop producing the hormones that initiate the menstrual cycle.

• Fluctuations in hormone levels: When estrogen levels start to fluctuate, it can alter the menstrual cycle, causing a change in period dates. This is very common in women in perimenopause or menopause.

• Changes in daily routine: Disruptions or changes in daily routine can have an impact on the menstrual cycle. Some examples of lifestyle factors include changes in sleep patterns, diet, or exercise.

• Certain medications: Certain medications, such as hormonal contraceptives, can affect the menstrual cycle and cause changes in period dates.

• Underlying medical conditions: Certain health conditions, such as polycystic ovary syndrome (PCOS), thyroid disorders, or uterine fibroids, can cause menstrual irregularities.

Its important to note that slight variations in cycle length or having a menstrual period that seems slightly heavier or lighter in flow than the previous period is normal. However, if after years of regular cycles, the period falls completely out of range of the regular cycle, its advisable to consult a doctor.