Infertility: The serious impact of endocrine disorders on female fertility

5.5 Infertility – Regulating endocrine function is key

5.5.1 What is the endocrine system?

The human body contains many glands, such as the thyroid gland, pancreas, sweat glands, and gonads, all of which have secretory functions. Secretion can be categorized into exocrine and endocrine processes. Exocrine secretions, produced by glands, are transported through ducts directly to the cavities of organs or the body surface. These secretions are liquid and are called exocrine secretions. For example, pancreatic juice secreted by the pancreas travels through the pancreatic duct to the small intestine, and sweat secreted by sweat glands reaches the body surface. Endocrine secretion, on the other hand, is a special type of secretion in the human body, produced by endocrine glands. Endocrine glands do not have ducts, and their secretions, called hormones, are transported throughout the body via the blood or lymphatic system and exert their effects in specific locations. For instance, thyroid hormones produced by the thyroid gland are directly secreted into the bloodstream and circulate to certain parts of the body to produce their effects.

The main endocrine glands in the human body include: pituitary gland, thyroid gland, parathyroid gland, adrenal gland, pancreas, and gonads.

Glands that perform endocrine functions are called endocrine glands, and their secretions are called hormones. Hormones have a wide range of effects, involving the body's growth, development, environmental adaptation, and stress response. The endocrine system is closely linked to the central nervous system in terms of physiological function, working in close coordination and interaction to regulate various bodily functions and maintain relative homeostasis to adapt to changes and needs in the internal and external environments. The endocrine system is indirectly or directly regulated by the central nervous system; it can also be considered a part of the central nervous system's regulatory system. The endocrine system secretes various hormones, working with the nervous system to regulate the body's metabolism and physiological functions. Under normal circumstances, various hormones are in balance. If this balance is disrupted for some reason (too much or too little of a certain hormone), endocrine disorders will occur, with the following clinical manifestations.

① Menstrual irregularities: Menstrual irregularities are a common symptom in patients with endocrine disorders, mainly caused by excessively high or low levels of estrogen secretion from the ovaries.

②Obesity: Many patients with endocrine disorders are obese, and obesity can also easily cause endocrine disorders. This is related to an individual's endocrine regulation and dietary habits.

③ Deteriorating skin condition: Hormonal imbalances in women can easily lead to age spots and other pigmentation issues, affecting their skin.

④ Negative emotions: Irritability is also a common symptom in patients with endocrine disorders, which is generally caused by a decline in endocrine function.

Endocrine disorders, also known as endocrine imbalances, can occur in both men and women, but women tend to experience more pronounced symptoms, which are more likely to attract attention and prompt corresponding prevention and treatment. Therefore, endocrine system diseases are closely related to the organs or glands and hormone levels within the endocrine system.

5.5.2 The Influence of Endocrine Functions on Female Fertility

The number of women with endocrine disorders is rising every year, which is related to factors such as high stress levels, living environment, diet, and lack of sleep. So, how does endocrine disorder affect a woman's fertility?

Endocrine disorders are a significant cause of female infertility. Normal function of the hypothalamus-pituitary-ovarian axis is fundamental for establishing a normal ovulation cycle in women. Dysfunction in any part of this axis, resulting in excessive or insufficient hormone secretion, can disrupt metabolism and lead to anovulation, reduced or absent ovulation, amenorrhea, polycystic ovary syndrome, hirsutism and virilization, hyperprolactinemia, luteal insufficiency, dysfunctional uterine bleeding, ovulation bleeding, and hypolipidemia (total fat below 6% of body weight). These conditions can further contribute to ovarian insufficiency and premature ovarian failure. Infertility caused by these endocrine factors is termed endocrine-related infertility.

The causes of infertility due to endocrine disorders are complex, mainly including abnormal ovulation and luteal phase dysfunction.

1) Adrenal factors: Increased secretion of adrenal cortex hormones can, in turn, reduce pituitary hormones and estrogen secretion from the ovaries, affecting ovulation. This can lead to oligomenorrhea, delayed menstruation, amenorrhea, and infertility in women.

2) Hypothalamic-pituitary-ovarian axis: also known as the sex axis, menstruation is related to the sex axis. Any abnormality in any link of the sex axis may lead to dysfunction of the sex axis, which in turn can cause menstrual disorders, dysfunctional uterine bleeding, incomplete development of the corpus luteum, amenorrhea and other conditions.

3) Pancreas: The pancreas secretes insulin, and its main function is to regulate glucose metabolism. Recent studies have found a certain relationship between it and the sex axis. Menstrual irregularities and amenorrhea in women, which may lead to infertility, are related to the pancreas.

4) Thyroid gland: Thyroid dysfunction commonly presents with two conditions: hyperthyroidism and hypothyroidism. Hyperthyroidism in women can lead to oligomenorrhea, delayed menstruation, or even amenorrhea; hypothyroidism can lead to menorrhagia, early menstruation, etc.

5.5.3 The Relationship Between Obesity and Endocrine Function

Obesity can be mainly divided into the following three categories.

The first type, simple obesity, is caused by excessive energy intake due to diet, exercise, and unhealthy lifestyle, which leads to the accumulation of energy in the body, causing obesity and endocrine disorders.

The second type is endocrine-related obesity. Endocrine abnormalities are often accompanied by secondary obesity. Conditions such as hypothyroidism, polycystic ovary syndrome, cortical insufficiency, and Cushing's syndrome can all lead to obesity. Endocrine abnormalities often affect fat metabolism. Lipopolysaccharide (LPA) is a core component in the body's breakdown, conversion, and reduction of fat, accelerating the rate of fat breakdown. The lower the LPA level in the body, the easier it is for a person to gain weight, leading to long-term fat accumulation. This explains why some people gain weight even when eating very little. Similarly, some people have excessive LPA secretion, resulting in rapid fat breakdown. Therefore, people with balanced endocrine systems are less likely to become obese.

The third type is familial idiopathic obesity. This condition often has no identifiable cause; endocrine tests show no abnormalities, and the patient doesn't eat much. It is generally associated with genetic predisposition and a hereditary background.

Therefore, obesity and endocrine disorders are mutually causal. Obesity leads to endocrine disorders, and endocrine disorders, in turn, worsen obesity!

Xiao Qiao is a private business owner who runs a municipal company and a clothing store with her husband. Frequent social engagements caused Xiao Qiao, who is only 160cm tall, to weigh 76.9kg, classifying her as extremely obese. Almost all her health indicators were abnormal, accompanied by severe endocrine disorders and moderate fatty liver. After two months of adjustments using a healthy weight loss technique, Xiao Qiao's weight dropped to 54.5kg, her visceral fat decreased from 19 to 7, her fatty liver symptoms disappeared, and, most importantly, her endocrine regulation returned to normal, with her menstrual cycle gradually becoming regular.

Data before weight loss: Obesity level: extremely obese, weight 76.9kg, body fat percentage 43.7%, fat 33.6kg, visceral fat 19.0kg, protein 7.8kg, water 33.0kg, muscle 40.8kg, skeletal muscle 29.1kg, bone mass 2.5kg.

Post-weight loss data: Obesity level: moderate obesity, weight: 54.5kg, body fat percentage: 26.5%, fat: 14.4kg, visceral fat: 7.0kg, protein: 7.1kg, water: 30.4kg, muscle: 37.5kg, skeletal muscle: 26.7kg, bone mass: 2.6kg.

Note: This data comes from the Bianla APP.

Healthy weight loss has a significant effect on regulating endocrine function.