Understanding the Impact of Contest Prep: Why Women Lose Their Menstrual Cycle

Steff Noble, Pro Prep Head Coach, WNBF Pro

Competitive bodybuilding and physique competitions require athletes to achieve an exceptionally lean and sculpted physique. 

To reach this level of conditioning, both male and female competitors often undergo rigorous dieting and training protocols. 

However, one notable phenomenon that commonly occurs among women during contest preparation is the loss of their menstrual cycle, known as amenorrhea. 

Let’s explore why and how women experience this change in their menstrual cycle during contest prep…

Pro Prep Female Team Champions

Contest preparation typically involves a combination of calorie restriction, intense training, and increased cardiovascular exercise. The goal is to reduce body fat levels to extremely low percentages, which can push the body to adapt in various ways. For women, the stress placed on the body through this process can disrupt the delicate balance of hormones involved in the menstrual cycle.

One of the primary causes of menstrual cycle disturbances during contest prep is energy imbalance. The significant reduction in calorie intake that often accompanies contest preparation can result in a state of energy deficiency or low energy availability. When the body perceives this energy deficit, it triggers a series of hormonal adaptations to conserve energy and protect vital bodily functions.

Low energy availability affects the hypothalamic-pituitary-ovarian axis, which is responsible for regulating the menstrual cycle. The hypothalamus, a region of the brain, releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to produce follicle-stimulating hormone (FSH) and luteinising hormone (LH). These hormones are essential for ovulation and the maintenance of a regular menstrual cycle.

However, during contest prep, the reduced calorie intake and increased energy demands can disrupt the normal functioning of the hypothalamus. The hypothalamus may reduce the release of GnRH, leading to a decrease in FSH and LH production. As a result, ovulation may be suppressed or cease altogether, causing the loss of the menstrual cycle.

Additionally, contest prep often involves extremely low body fat levels, which can further impact hormonal balance. Adipose tissue, or body fat, plays a crucial role in hormone production. Estrogen, in particular, is synthesized and released from adipose tissue. When body fat levels drop to extremely low levels, estrogen production can be significantly reduced. Estrogen is necessary for the growth and maintenance of the uterine lining, and its deficiency can disrupt the menstrual cycle.

The loss of the menstrual cycle during contest prep is not only a result of hormonal changes but also serves as an adaptive response by the body. When the body perceives the stress associated with low energy availability and intense training, it priorities essential functions to ensure survival. Reproduction is considered non-essential from a physiological standpoint in times of stress, and the body redirects resources away from reproductive processes to preserve energy.


Not every woman will lose her period during contest prep or extreme dieting. The occurrence of menstrual disturbances, such as amenorrhea, can vary among individuals based on various factors, including genetics, body composition, overall health, and the specific protocols followed during contest preparation.

While many women may experience changes in their menstrual cycle during contest prep, some may maintain regular menstruation throughout the process. Factors such as the extent of calorie restriction, duration of low energy availability, training intensity, and overall stress levels can influence whether or not a woman retains her menstrual cycle.

It’s important to note that the loss of the menstrual cycle is not an indicator of success or achievement in contest preparation. In fact, the absence of menstruation can be a sign of underlying health concerns and should be addressed with the guidance of healthcare professionals.

Each woman’s body is unique, and responses to extreme dieting and exercise can vary. It is crucial for women considering contest prep or any intense dieting regimen to prioritise their overall health and well-being. Seeking guidance from healthcare professionals, including sports medicine physicians and registered dieticians, can help ensure a balanced and sustainable approach to competition preparation while minimising potential negative effects on the menstrual cycle and overall health.


While the loss of the menstrual cycle may be a common occurrence during contest prep, it is important to recognise the potential health implications. Amenorrhea can have long-term consequences, including a decrease in bone mineral density, increased risk of stress fractures, and hormonal imbalances. Therefore, it is crucial for women to work closely with healthcare professionals, such as sports medicine physicians and registered dieticians, to monitor their health and mitigate the potential risks associated with amenorrhea.

To regain a regular menstrual cycle, it is often necessary to address the underlying causes of energy deficiency. This may involve increasing calorie intake, improving nutrient balance, and allowing the body to reach a healthier body fat level. It is important to note that restoring the menstrual cycle can take time and patience, as hormonal balance does not typically recover immediately.

In conclusion, the loss of the menstrual cycle during contest prep is a complex interplay of energy availability, hormonal adaptations, and the body’s response to stress



Finally if you want to make sure you’re getting the right advice and want to ensure you are navigating a female prep with health as a priority we encourage you to speak with us.

We use an evidence based approach to get our clients into stage ready condition. As always if you think we can help you then hit that link and book a free call with us today – Click Here.