At puberty, the distance between the iliac crests of the female pelvis, measured by the intercristal and interspinous diameters, increases rapidly. This is mainly controlled by
estrogens. We have followed up 6,370 women who were born in Helsinki during 1934-1944, and whose mothers' pelvic bones were measured during routine
antenatal care. We have previously reported that women whose mothers had larger intercristal diameters had higher rates of
breast cancer. We postulated that large intercristal diameters are markers of high circulating concentrations of
estrogen, which are established at puberty, persist through reproductive life and cause genetic instability in differentiating breast cells in female embryos. We now report on
ovarian cancer in the same cohort. Our hypothesis was that the risk of this
cancer would also be higher in women whose mothers had broader hips. We found that, when compared with all other women, the hazard ratio for
ovarian cancer was 3.3 (95% CI 1.6-7.0, P = 0.004) in the daughters of mothers whose interspinous diameter was greater than 27 cm. Among mothers who had an early menarche, each measure of broad hips was associated with increased risk of
ovarian cancer in their daughters. We postulate that
ovarian cancer is initiated by exposure of the fetal ovary to maternal
sex hormones. Concentrations of these
hormones may be higher in mothers who had an early menarche. The maternal
sex hormone profile that initiates
ovarian cancer may be the product of poor nutrition and growth in early childhood followed by catch-up pre-pubertal growth.