Abnormal development of reproductive organs can lead to primary amenorrhea

Primary amenorrhea refers to the absence of menstruation at the age of 14 and the lack of development of secondary sexual characteristics, or the absence of menstruation at the age of 16, regardless of whether the secondary sexual characteristics are normal. Abnormal development of reproductive organs is an important factor in primary amenorrhea:

Imperforate hymen

Hymen occlusion is caused by the vigorous development of the folds of the hymen, which prevents the vagina from penetrating the vestibule of the vulva. Hymen occlusion is often found at the time of menarche. If the uterus and vagina develop normally, menstrual blood will accumulate in the vagina after menarche, and then expand to the uterus, forming vaginal and uterine hematomas. Excessive blood accumulation can flow into the fallopian tube and enter the abdominal cavity through the fimbria. The peritoneum near the fimbria is stimulated by menstrual blood and edema and adhesion occurs, causing the fimbria of the fallopian tube to be blocked, forming vaginal, uterine, and fallopian tube hematomas. Menstrual blood entering the abdominal cavity can form endometrial implants, causing endometrial migration.

Hymen occlusion leads to primary amenorrhea because the urogenital sinus epithelium does not penetrate the vulva and vestibule, and the ovaries and secondary sexual characteristics develop normally. Periodic abdominal pain is often found during adolescence, and there is also a lower abdominal mass due to blood accumulation in the vagina and uterine cavity. Severe cases can cause compression symptoms such as frequent urination, urinary retention and constipation.

Congenital absence of vagina

Congenital absence of vagina is caused by internal or external factors blocking the embryo during development, or by abnormal development of the paramesonephric duct due to gene mutation. It is characterized by normal female chromosome karyotype, normal systemic growth and development of female secondary sexual characteristics, normal vulva, vaginal absence, uterine development, small fallopian tubes, and normal ovarian development and function. A few are true hermaphroditism or gonadal dysgenesis. Congenital absence of vagina leads to amenorrhea because the paramesonephric duct stagnates and does not extend downward, and the ovaries are normal.

Congenital absence of uterus

Congenital absence of uterus is the most common type of reproductive organ malformation. During the evolution process, the bilateral mesonephric ducts are affected and disturbed by certain factors, and may stop developing at different stages of evolution to form various developmental abnormalities of the uterus. The cause of primary amenorrhea is the failure to develop the middle and tail of the mesonephric ducts.