(1) Routine Semen Analysis for Men At the initial diagnosis of infertility, regardless of whether there is a history of fertility, men should first undergo routine semen analysis. This involves testing various parameters according to the fifth edition of the WHO standards, and performing staining analysis on morphologically abnormal sperm. If the results are abnormal, 2 to 3 retests are conducted for confirmation. If the semen analysis shows abnormalities, or if there are sexual function and ejaculation disorders, it is advisable to consult a reproductive urology specialist.

(2) Ovulation Monitoring for Women This is arranged at the initial diagnosis.

  1. Measurement of Basal Body Temperature This is a classic and practical method for detecting ovulation. By continuously monitoring and plotting the basal body temperature curve, an increase of 0.3 to 0.5°C after ovulation is observed, lasting ≥12 days. Since body temperature rises post-ovulation, monitoring is retrospective. For young women who have not been cohabiting long and have plans to conceive, this method can initially determine if ovulation occurs and establish a pattern. Basal body temperature also has diagnostic significance for insufficient luteal function, where a high-temperature phase lasting ≤11 days suggests a preliminary diagnosis.
  2. Dynamic Ovulation Monitoring via Transvaginal Ultrasound Transvaginal ultrasound monitoring is a very popular and practical method for infertility diagnosis. The basic ultrasound report should include: uterine shape and size, ovarian volume, the number of antral follicles 2-10mm in diameter (AFC), dominant follicle diameter, endometrial thickness and type, and pelvic conditions. Special attention should be paid to monitoring AFC in patients with decreased ovarian function, with early follicular phase monitoring being relatively accurate. Normal AFC values are ≥9, while ≤5-7 indicates decreased ovarian function. The normal range for a mature follicle diameter is 18-25mm; if ovulation is abnormal, monitoring for 2-3 cycles is required. The endometrium is classified into types A, B, C, reflecting its echo pattern at different stages of the cycle under the influence of estrogen and progesterone: type A during the proliferative phase, type B at ovulation, and type C during the secretory phase. The endometrial thickness increases with follicle growth, typically around 9mm in double layers before ovulation.
  3. Hormone Levels Generally tested in cases of abnormal ovulation, decreased ovarian function, and in older women (>35 years). Initial hormone screening in infertility includes: (i) Luteal phase progesterone levels, the gold standard for assessing ovulation, indicating the occurrence of ovulation and luteal formation. A progesterone level >3ng/L suggests ovulation; <3ng/L confirms anovulation. (ii) Day 2-3 levels of FSH, LH, E2, PRL, T, TSH, reflecting the baseline endocrine status of the ovaries and screening for potential thyroid dysfunction, hyperprolactinemia, and hyperandrogenism, which can cause ovulatory disorders. (iii) Pre-ovulation blood and urine LH testing to monitor and capture the peak of endogenous LH, predicting ovulation occurring approximately 36 hours after the peak. Dynamic estrogen levels also reflect follicular development, with follicles ≥14mm generally producing about 300pg/L of estrogen. Based on these hormone tests, the site of the ovulatory disorder—whether hypothalamic, pituitary, or ovarian—can generally be determined.
    1. Other Tests Laparoscopy can observe ovarian surface follicles, corpora lutea, and even the process and traces of follicle release; histological changes in the endometrium during the luteal phase (pre-menstrual) in a natural cycle, showing “secretory phase” alterations due to progesterone action, serve as evidence of ovulation. However, diagnosing luteal phase deficiency based on endometrial secretion is challenging.