The leading causes of developmental disorders of the female reproductive tract are genetic abnormalities and some medications. Given the complexity of fetal development, many factors can derail the process.
Among genetic factors is a defect that prevents production of 21-hydroxylase, causing a girl to be born with ovaries, a uterus and fallopian tubes, but external sex organs that look like a boy’s. The exact cause of intersex disorders is not known, but they arise from problems involving abnormal configurations of the XY and XX chromosome pairs that control gender development. In some cases, the baby has an extra Y or X chromosome, which can lead to an imbalance of sex hormones, problems with sexual development and affect the number of sex chromosomes. In gonadal intersex, a person has both ovarian and testicular tissue, and may have female chromosomes, male chromosomes or both. Animal studies indicate that exposure to agricultural pesticides causes gonadal intersex.
Genetic abnormalities also lead to ambiguous genitalia, the development disorder in which external genitals do not appear to be those of either a boy or a girl. Disruptions in the process of becoming one gender or another can lead to the baby being female but having a male appearance.
Mayer-Rokitansky-Küster-Hauser syndrome results in the vagina and uterus being underdeveloped or missing. The exact reason for the abnormality is not known. It can be inherited but most cases occur in people with no prior history. Studies have yet to associate a cause with drug use, illness or other factors.
Medications are other causes of developmental disorders of the female reproductive tract. At one time, doctors prescribed a drug known as DES (diethylstilbestrol), to prevent miscarriage and early labor, until studies showed it led to birth defects and vaginal cancer. Exposure of a pregnant woman to testosterone is another potential cause of developmental disorders. Supplements containing DHEA also may lead to hormonal imbalances that can affect fetal development.