Diethylstilbestrol (DES) was developed in the late 1930s and prescribed to women at risk for having miscarriages and preterm labor. DES is a synthetic estrogen and acts biologically similar to currently available estrogenic compounds. It was initially reported to improve pregnancy outcome, but later studies did not report any difference, but despite such evidence, its use continued until it was banned in the US in 1971.
It was noted that daughters of women who took DES during early pregnancy had an unusual type of vaginal cancer at young ages. Additionally, abnormalities of the cervix, vaginal cavity and structural problems of the uterus were reported. Approximately, 70-80% of women exposed to DES in-utero have some form of an abnormality in their uterus and the most commonly encountered problem is called a T-shaped uterus. Women exposed to DES are at risk for having miscarriages, preterm labor, ectopic pregnancy, vaginal cancer and cervical incompetence.
It is unknown how many women were exposed to DES over the years, but it is estimated to be a few million in the US. Most women exposed to DES are exiting their reproductive years, but there are still a few who may have poor reproductive outcome and need close surveillance and treatment. Others need to be gynecologically examined on a regular basis for the unusual type of vaginal cancer called the clear cell carcinoma. DES exposed males are believed not to be affected in regards to fertility or sexual function. Although some early studies suggested an association, it was not confirmed by later reports.
T shaped uterus can be due to DES exposure or a congenital malformation that can result in decreased fertility, increased risk for miscarriage and complications during pregnancy such as preterm labor and prematurity related complications in the newborn. Whereas there is no surgical or medical treatment for a T-shaped uterus, close surveillance during early pregnancy with hormonal support and possible cerclage placement in the second trimester can be considered. Most patients with a T-shaped uterus who are closely followed during pregnancy can have a full term and an uncomplicated pregnancy.
In patients with a history of failed In Vitro Fertilization (IVF) cycles and in the presence of good quality embryos, a uterine abnormality can often be the cause of treatment failure such a T-shaped uterus. It may be challenging to diagnose a T-shaped uterus during hysteroscopy, but an experienced fertility specialist can suspect such a problem by patient’s history and document it based specific findings during surgery.
When DES exposed uterus or a T-shaped uterus is confirmed, alternative treatment options should be discussed with patients to maximize pregnancy or IVF treatment outcome. One option is to continue management by supporting the pregnancy with hormone treatment and close surveillance. Another approach is to use a gestational carrier, if the couple is undergoing IVF treatment. Embryos can be created and even tested for chromosomal abnormalities, and normal ones can be transferred selectively into the uterus of the gestational carrier, minimizing the risks associated with a T-shaped uterus. It is highly recommended to consult with a fertility specialist who has experience in treating such abnormalities. In most cases, a favorable outcome can be accomplished with directed treatment.