Menstrual Irregularity Causes and Implications

Physiological Basis and Common Causes

The menstrual cycle depends on a complex interplay of hormones within the hypothalamic-pituitary-ovarian axis, which is naturally sensitive to various internal and external factors 1
Stress can disrupt luteinizing hormone (LH) pulsatility, which disturbs gonadotropin release and results in temporary menstrual dysfunction 1
Psychological stress can lead to functional hypothalamic amenorrhea, which accounts for 20-35% of secondary amenorrhea cases 1
Low energy availability disrupts the hypothalamic-pituitary-gonadal axis, leading to disruptions in LH pulsatility and causing oligo-amenorrhea 1
The female athlete triad (energy availability, bone health, and menstrual status) can lead to menstrual irregularities 1
Polycystic ovary syndrome (PCOS) is one of the most common causes of menstrual irregularity, affecting approximately 4-6% of women 2

Inconsistent or incorrect use of hormonal contraceptives is a major cause of menstrual irregularities 3, 4
Missing hormonal contraceptive pills, especially extending the hormone-free interval, can disrupt the menstrual cycle 4
Unscheduled spotting or bleeding is common during the first 3-6 months of extended or continuous hormonal contraceptive use 3

Occasional menstrual irregularity is generally not harmful but can be an indicator of underlying health issues if persistent 1
Persistent low estrogen levels due to amenorrhea can lead to decreased bone mineral density and increased risk of stress fractures 1
The first step in diagnosis for missed periods is a pregnancy test 1
Initial laboratory evaluation should include serum FSH, LH, prolactin, and TSH levels to identify potential causes 1
Women with epilepsy and menstrual irregularities should be evaluated for reproductive endocrine disorders, as they have a higher prevalence of PCOS 2