9 Causes of a Long Menstrual Cycle
A long menstrual cycle is characterized by being longer than 35 days or more. Day 1 counts as the first day of a full bleed and the cycle are counted up until the day before your next period.
If your cycle is long or irregular this is because ovulation is either delayed or not happening. It’s important to uncover why ovulation may not be occurring or if it is delayed. A true period always follows ovulation. Your period will always occur 12-16 days after ovulation (this is the luteal phase).
A healthy cycle is reliant on stable hormone levels. If one hormone is elevated or low, this will send a cascade of off levels for the rest of the cycle. If you are not getting a period for three months or more, then it’s important to start digging a little deeper because this is characterized as amenorrhea and can have detrimental long term health problems.
Here are 9 possible causes of a long menstrual cycle - and you could have more than one!
1. PCOS
Polycystic ovarian syndrome or PCOS is one of the causes of a long menstrual cycle. Diagnosis of PCOS is by having 2 of the 3 symptoms to follow polycystic ovaries on ultrasound, elevated androgen levels, and anovulatory cycles. The reason that PCOS is one of the causes of a long menstrual cycle is that if you have increased androgen levels, this results in anovulation and long menstrual cycles. Having the second two symptoms of PCOS is one of the causes for long menstrual cycles because they indicate you have hormonal imbalances.
2. High Androgens
Similar to PCOS, another one of the causes of a long menstrual cycle is high androgens. Testosterone is one of the androgens in females that typically are low during normal hormone levels. Testosterone can become elevated due to stress levels, sleep problems, or blood sugar imbalance. When blood sugar is imbalanced we have high levels of insulin in the bloodstream that is not being utilized by the cells to shuttle glucose. Since insulin is a hormone, it has an impact on other hormones throughout the body, and as a result, it can stimulate the ovaries to increase testosterone production. Testosterone increase causes estrogen to decrease and this negatively impacts ovulation.
Another androgen is called DHEA which is an enzyme that combines with testosterone to make DHT, another testosterone-like compound. DHEA levels are highly impacted by stress and cortisol. Put together the cortisol levels and the high DHEA make a powerful combination to inhibit ovulation which is one of the causes of a long menstrual cycle.
3. Thyroid Issues
Thyroid issues are another one of the causes of a long menstrual cycle. The thyroid is a gland in our throat that needs to release hormones to maintain a stable metabolism among other things. If these hormones are not released as frequently as they should, then this is called low thyroid or in more intense situations, hypothyroidism. Our body will try to stimulate more thyroid hormone output, so additional hormones in the brain, specifically in the hypothalamus, will be released to try to generate more thyroid hormones. These hormones, unfortunately, therefore, can inhibit the action of other sex hormones causing infertility. There are also structural changes to the follicles in the thyroid that can also increase the prolactin production and will therefore decrease progesterone. Progesterone is a necessary hormone for ovulation. Its name literally means to promote gesterone or gestation, so if it is not produced enough this can be one of the causes of a long menstrual cycle. The mechanism behind prolactin’s effect on progesterone will be touched on next.
Source: 9846161
4. High Prolactin
Prolactin is a hormone that affects progesterone and ovulation. Prolactin allows the breasts to produce milk at the end of pregnancy and postpartum. Usually, if we are not pregnant prolactin levels should be low, though they can elevate. It is most commonly seen in women with PCOS, to have high prolactin levels. Along with inhibiting progesterone, prolactin also inhibits FSH, a hormone necessary in the beginning of the menstrual cycle for ovulation.
Source: 23814712
5. Undereating
Another one of the causes of a long menstrual cycle is undereating. Eating below your body’s energy requirement is detrimental to your hormone balance which affects ovulation. Undereating can be identified as skipping meals, decreasing the size of meals, or decreasing the composition of variety in your food choices. Though every case is different, it is important to signal that these undereating behaviors can be causes of a long menstrual cycle. These patterns put our body into a state of panic and stress because we are trying to survive at an energy level insufficient for our current size. From this stress, estrogen levels decrease and ovulation is not possible because our body is worried we will not be able to carry a full-term pregnancy at a lower weight. Our body fat percentage is most likely decreasing as well due to the under eating and therefore estrogen levels will be very low due to this.
Source: 7021778
6. Overexercising
Similar to undereating, overexercising is another one of the causes of long menstrual cycles. Over-exercising can cause long menstrual cycles because of the high stress it puts on the body. Over-exercising can be identified as any exercise performed at a high frequency, duration, and intensity during the week with minimal to no rest days. It is important to note that exercising, in general, is okay and actually beneficial for hormone levels, but it is the excessive nature of exercise that is harmful. The main issue with this is that our bodies need a stable body fat percentage to maintain a normal menstrual cycle, and estrogen levels will drop as body fat drops. As a rule of thumb, most females need at least 17% body fat to maintain a normal menstrual cycle to ovulate.
7. Stress
Stress is another one of the causes of a long menstrual cycle. When we are stressed we release high levels of cortisol, a stress hormone. In response to this, our body perceives it is under a threatening situation so the body will pump the brakes to avoid pregnancy and will put energy towards priority body functions. In this state, our hormone production, digestion, and detoxification of hormones will slow down causing a large imbalance in our hormonal system. Due to these hormone shifts, this is why stress is one of the causes of a long menstrual cycle.
Source: NIH
8. Hypothalamic Amenorrhea
Hypothalamic amenorrhea is another one of the causes of a long menstrual cycle. The hypothalamus is an area of the brain that controls all of our basic needs for homeostasis like thirst, hunger, blood pressure, and heart rate. Attached to it is the pituitary gland, which is responsible for producing many of the hormones. Amenorrhea is when you do not have a period for 3 consecutive cycles. So as a result, hypothalamic amenorrhea is when you do not have a period for 3 consecutive months due to the low production of the pituitary gland in the brain caused by hypothalamic stress. Things like undereating, overexercising, low body fat percentage and low carbohydrate intake are all factors that can threaten the hypothalamus and shut off hormone production in the pituitary. One important hormone specifically that is effected it GnRH, which when released will cause FSH and LH, other reproductive hormones, to be excreted and promote ovulation.
Source: NIH
9. Nutrient Deficiencies
Many nutrients are highly impactful on hormone production and regulation.
Vitamin B6 deficiency can be another one of the causes of a long menstrual cycle. Vitamin B6 is a water soluble vitamin that can aid in healthy brain development, curing morning sickness, and immune function. Estrogen metabolism is another one of the properties of Vitamin B6 which helps convert estrogen into its active form.
Zinc is another vital mineral for pregnancy, so if levels are low it can be what causes long menstrual cycles. It has been shown that low levels of zinc have been correlated with a longer time to conceive. A large function of zinc is its antioxidant function, which helps to balance hormones because of decreased stress and inflammation.
Magnesium deficiency is one of the causes of a long menstrual cycle because magnesium is a highly important supplement for pregnancy. Some of its main benefits include increasing fetal development, protein synthesis, and stable nerve cell function.
Source: 6684167, Oxford University, 6684167
