Methods of Assessment for Female Infertility

Infertility is a complex condition affecting both men and women that can impede reproduction. Accurate diagnosis and assessment of this condition are paramount. The treatment plan for infertility should consider factors such as age, duration of infertility, cause of infertility, convenience of access to medical care, and costs. Particularly, it is crucial to determine the diagnostic and treatment process based on the significance and logical rationale of each test.

(1) Age of the Infertile Couple The optimal reproductive age for couples is between 20 and 30 years old, especially for women. At birth, a female has about one million primordial follicles in her ovaries. By puberty, about 400,000 remain. From the ages of 15 to 45, ovarian follicles continually grow, but only about 400-500 follicles develop to maturity over these 30 years; the rest degenerate during development. By the age of 35, the number of ovarian follicles decreases, and the quality of oocytes deteriorates. By the age of 45, women generally reach the end of their reproductive period. Thus, there is a strong correlation between female infertility and age, making it the first factor to consider in infertility consultations and treatments.

Generally, the age of a woman with infertility is categorized into three stages:

Women under 30, with normal ovarian reserve and a short duration of infertility without absolute infertility causes, can expect to conceive by improving their lifestyle to facilitate pregnancy.
Women aged ≥35, if they have not conceived after six months of trying, should consult an infertility clinic for simple consultations and tests, such as a semen analysis for the male partner and an ultrasound through the vagina for the female to observe the number of antral follicles, roughly assessing ovarian reserve and pursuing active attempts at conception and assisted reproduction.
Women aged ≥40 with infertility should have their ovarian function tested and are advised to use assisted reproductive technologies like in vitro fertilization to aid conception.

(2) Duration of Infertility The capability of a couple to conceive within a unit of time (usually per cycle) is termed fecundability, which is about 25% for a “normal” couple under 35. Statistics show that about 80% of couples may conceive within the first year, about 50% of those not conceiving in the first year may naturally conceive in the second year, and approximately 95% can naturally conceive within three years. Therefore, medical intervention is generally recommended after three years of unprotected intercourse. However, in some cases, couples should seek medical advice and clinical treatment earlier:

Women over 35 years of age with infertility;
Women with a history of menstrual irregularities or amenorrhea;
Suspected or confirmed cases of uterine or tubal causes, or endometriosis;
Couples diagnosed with possible causes of infertility. For newly diagnosed infertile couples, both partners should initially undergo a complete history collection, a comprehensive physical examination, and systematic pre-pregnancy counseling to guide them in the most ideal conception methods and timings.

(3) Causes of Infertility Infertility arises from various causes. Theoretically, absolute causes of infertility include ovarian failure, complete bilateral tubal blockage, removal or obstruction, and azoospermia in males. Other related phenotypes are considered relative causes because patients with persistent anovulation, such as those with polycystic ovary syndrome, may occasionally ovulate and conceive, and it can be challenging to accurately assess the patency of fallopian tubes. Men with oligospermia are not absolutely unable to conceive naturally, and the severity of endometriosis often does not correlate with the occurrence of infertility. Therefore, accurately determining the cause of infertility is sometimes difficult.

To standardize the clinical diagnosis and treatment of infertility, a significant amount of evidence-based medical evidence is required to analyze and verify the causes of infertility. Thus, it is recommended to categorize the causes of infertility into four main categories for diagnosis and classification according to the industry standards of the Ministry of Health of China: