Epidemiologic data are few but suggest that effects during the prenatal and early life periods may be important in influencing risk of breast, prostate and testicular cancers later in life. In particular, evidence is accumulating for associations with several maternal, perinatal and pregnancy characteristics, including twining.

The effect of these factors may be mediated through alterations in hormone levels such as the estrogens and other steroid hormones, to which the embryo and fetus are exposed during pregnancy. Differences in maternal hormone concentrations by maternal and perinatal factors have been noted, though data for most factors are sparse.

Furthermore, less is known about the relationships of pregnancy factors to hormones in cord blood, the proximal exposure to the fetus, since most work thus far has been based on hormones in the maternal circulation. In collaboration with investigators at Dartmouth Hitchcock Medical Center, we are collecting maternal and cord blood samples from monochorionic twin, dichorionic twin and singleton pregnancies of similar gestational age to quantify differences in concentrations of several hormones and other pregnancy products. The purpose of the study is to assess the consistency of these data with hypotheses regarding the altered cancer risk daughters of twin pregnancies experience.