DES What is DES? DES (diethylstilbestrol) is a synthetic estrogen that was prescribed to millions of pregnant women between 1938 and 1971 to prevent miscarriage, premature birth, and other pregnancy complications. At the time, it was considered safe. Later research revealed that DES crosses the placenta , directly affecting fetal development and causing long-term health issues. Health Risks for DES-Exposed Children Exposure to DES in the womb can lead to serious and sometimes