A possible link between the pubertal growth of girls and ovarian cancer in their daughters.

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.