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What causes irregularity of a woman's menstrual cycle?

By Blogger September 17, 2014 - 8:34am
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I am wondering what can cause a woman's period to be late (besides pregnancy). For the past few months my menstrual cycle has been a week or more late - I have considered stress, anxiety and a change in lifestyle, but what are some other things that can cause your period to be 30-40 days apart? 

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Hello Hayden,

Thank you for your question. This is a question that gets asked quite frequently. Understanding the factors that control a woman's menstrual cycle can help determine the cause of a late or even missed period.

The menstrual cycle is regulated by the complex interaction of hormones: luteinizing hormone, follicle-stimulating hormone, and the female sex hormones estrogen and progesterone. The menstrual cycle actually begins on the first day of menstruation or menstrual bleeding.

Day one is the start of the follicular phase. The follicle stimulating hormone is produced in the pituitary gland. Its purpose is to get a follicle ready for ovulation. As many as 30 follicles can develop, but only one continues to grow and develop to release an egg.

A benign pituitary gland tumor can interfere with this phase of the menstrual cycle.

The ovulation phase follows with with a surge in luteinizing hormone and follicle-stimulating hormone levels. Luteinizing hormone stimulates ovulation. Estrogen level peaks during the surge, and the progesterone level starts to increase.

Heightened stress, be it physical or emotional, during the ovulation phase can ovulation and a delay in the onset or absence of a period.

The luteal phase is the last phase. Progesterone, which is released by the ruptured follicle that released the egg, rises. Estrogen levels have been rising to build up the uterine lining. If the released egg is not fertilized, progesterone and estrogen levels decrease. The endometrium or uterine lining is shed and menstruation begins.

Any hormonal imbalance, including hypothyroidism or hyperthyroidism can cause menstrual irregularities. PCOS or polycystic ovary syndrome causes relatively high and sustained levels of hormones, rather than the fluctuating levels seen in the normal menstrual cycle. This is another cause of menstrual irregularities.

I hope this information is helpful and answers your question.


September 17, 2014 - 9:04am
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