There are various factors that can put one at the risk of developing amenorrhea. Some of the risk factors are:
Eating disorder: People with eating disorders such as anorexia nervosa or bulimia are more prone to amenorrhea due to lack of body fat and other problems.
Family history: If a woman has cases of amenorrhea or early menopause, then there are chances that she may get amenorrhea too.
Excessive exercise: Strenuous exercises and rigorous athletic training can easily put one at amenorrhea risk.
Genetics: Change in the FMR1 gene, which also causes Fragile X syndrome
Ovarian failure: Due to receiving chemotherapy and radiotherapy
Structural abnormalities: Girls who have congenital abnormalities such as poorly developed genital and pelvic organs can be at the risk of developing amenorrhea
Other risk factors include:
Use of contraceptives
Tumor and its treatments
Impact of Amenorrhea on Fertility
Amenorrhea is a symptom of an underlying causes and the causes of amenorrhea can be varied depending on the cause. Amenorrhea can be caused due to the disorders of the outflow tract (uterus and vagina), ovary and ovulatory disorders, disorder of the pituitary and hypothalamus.
Each of the causes has a different implication in the realm of infertility. In case of the disorders of the outflow tract - these women can have normal or abnormal genital anatomy. In normal genital tract anatomy - the causes include cervical stenosis, ashrams syndrome and endometrial damage. The fertility prospects depends on the extent of the disease as this affects the site of implantation.
In women with abnormal genital tract anatomy - it can be associated with obstruction at the level of the vagina which is amenable to treatment and fertility is restored. In women with absent uterus, surrogacy/ adoption is the only fertility option available. Uterine transplantation is another option which may be available in the future- It is still in the early stages of development.
Ovarian disorders can be further divided into chronic anovulation (where ovulation does not occur regularly and cyclically) and ovarian failure.
In women with chronic anovulation (eg. PCOS, Thyroid disorders) - treatment of the underlying disorder establishes ovulation and then pregnancy.
In women with ovarian failure (Causes- ovarian dysgenesis, premature ovarian failure, chemotherapy, radiotherapy) - in these women natural conception is difficult as the ovarian reserve is very low or non-existent - donor gametes is an option for pregnancy.
In pituitary and hypothalamic causes, the ovarian reserve is not affected, fertility is restored upon treatment of the cause of amenorrhea. Hence probability of pregnancy in amenorrhea is dependent on the underlying cause and each individual is evaluated and treated for fertility as per the same.