A 3 mg/day dosage of DES has been associated with an incidence of thromboembolism of 9.6 to 17%, with an incidence of cardiovascular complications of 33.3%. A lower dosage of 1 mg/day DES has been associated with a rate of death due to cardiovascular events of 14.8% (relative to 8.3% for orchiectomy alone). Other long-term effects
DES has been linked to a variety of long-term adverse effects, such as increased risk of 

vaginal clear-cell adenocarcinoma
vaginal adenosis
T-shaped uterus
uterine fibroids
cervical weakness
breast cancer
infertility
hypogonadism
intersexual gestational defects
depression,
and others,in women who were treated with it during pregnancy, and/or in their offspring.A comprehensive animal study in 1993 found a plethora of adverse effects from DES such as (but not limited to) 

genotoxicity (due to quinone metabolite)
teratogenicity
penile and testicular hypoplasia
cryptorchidism (in rats and rhesus monkeys),
liver and renal cancer (in hamsters), ovarian papillary carcinoma (in canines), and
malignant uterine mesothelioma (in squirrel monkeys). Evidence was also found linking ADHD to F2 generations, demonstrating that there is at least some neurological and transgenerational effects in addition to the carcinogenic.Rodent studies reveal female reproductive tract cancers and abnormalities reaching to the F2 generation, and there is evidence of adverse effects such as irregular menstrual cycles intersexual in grandchildren of DES mothers. Additionally, evidence also points to transgenerational effects in F2 sons, such as hypospadias. At this time however, the extent of DES transgenerational effects in humans is not fully understood. Overdose
DES has been assessed in the past in clinical studies at extremely high doses of as much as 1,500 to 5,000 mg/day.
With both the electron and confocal laser microscopy, it was prevalent that the Sertoli cells, which is a somatic cell where spermatids develop in the testes, was formed thirty-six years later in the rats who were injected with Diethylstilbestrol compared to the rats in the control group. Proceeding the completion of the trial, it was understood that rats of older age who were injected with DES experienced delay in sertoli cell maturation, underdeveloped epididymides, and drastic decrease in weight compared to its counterparts.The female rats used were inbred and most of them were given DES combined in their food. These rats were divided into three groups, one group who received no diethylstilbestrol, one group who had DES mixed into their diet, and the third group who had DES administered into their diet after day 13 of being pregnant. Some rats who were given DES unfortunately died before delivering their pup. The group that received DES in their food for 13 days while being pregnant resulted in early abortion and delivery failure. These outcomes showed that DES had a detrimental effect on pregnancy when administered as often as it was. Providing the dosing of diethylstilbestrol later in the pregnancy term also made visible the occurrence of abortions among the rats. Overall, any interaction with DES in female rats concluded in the rats experiencing abortions, improper fetal growth, and the increase in sterility.A review of people who had been treated or exposed to DES was done to find out how long-term effects would show.