To study the changes of six sex hormones corresponding to the follicle growth during the normal menstrual cycle of Chinese women.

Thirty Chinese women with regular menstrual period and average age of (28.8±3.2) years were selected for the study by Peking Union Medical College Hospital in September, 2010. Growth of follicles was monitored by using transvaginal sonography. Six sex hormones, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E₂), progesterone (P), testosterone (T), and prolactin (PRL) were measured by chemoluminescence immunoassay every day during a menstrual cycle. Nonparametric statistical analysis was used.

Menstrual cycle of all the patients was in the range of 25 to 39 d, with mean of (29.5 ± 3.1) d. Length of follicular phase and luteal phase was 15.3 and 14.4 d, respectively.Number of days from antral follicle to emergence of dominant follicle, and from the latter to ovulation, was 6.2 and 8.9 d, respectively. Average diameter of preovulatory follicle was 19.33 mm. Both FSH and LH reached peak on the day before ovulation. P started to increase before ovulation and remained at a high plateau from 6th to 9th day after ovulation. Both PRL and T reached peak after ovulation, near the end of a menstrual cycle.

A small rise of LH and P emerges just 1 to 2 d before ovulation, indicating the maturing of follicle. PRL and T shows cyclic changes as follicle grows. Therefore, PRL and T levels should be measured in the early follicle phases in the clinical practice so that leading the impact of menstrual cycle minimal.(Chin J Lab Med, 2017, 40: 169-173)

Menstrual cycle; Ovarian follicle; Gonadal steroid hormones; Luminescent measurements; Immunoassay