An absence of periods is called Amenorrhea. If you have never had a period even after the age of 15 this is called primary amenorrhea. If you have had periods in the past but no longer have them and are not currently pregnant than this is called secondary amenorrhea.
The longer your period has been absent the longer it will likely take to restore normal ovulatory and menstrual function. A general rule when treating the menstrual cycle is patience and commit to no less than 3 months. You will need to wait that long because it takes the ovarian follicles 100 days to complete its maturation and ovulation.
The main causes for a missing period is stress or illness. It happens because the command center of the brain(Hypothalamic - pituitary–adrenal axis) HPA decided to temporarily stop ovulating because the stress input has been interpreted by the brain that this is a dangerous time and not good to bring a baby into the world. So It shuts down reproduction. When this occurs, it is called Functional Hypothalamic Amenorrhoea.
The two reasons why the body decides to turn of reproduction is if it senses stress or malnutrition.
Stress and a low carb diet are the main causes of functional hypothalamic amenorrhea. Other reasons include depression, drug use, eating disorder, excessive exercise and low body fat.
By addressing the causes of hormone imbalance ovulation and menstruation will ensue. Chinese medicine is a tool that can be used to improve hormonal states by influencing the nervous system and the HPA axis in the brain, whilst also assisting to reduce stress, cortisol and insulin levels. These can be major factors influencing fertility. Acupuncture can also be used to promote circulation of blood into the pelvic cavity, improve the uterine lining and ovarian function and promote follicle production.