Epithelial ovarian carcinoma and fertility of parents

Intergenerational transmission of reproductive behaviour in Botswana

The purpose of this study was to investigate intergenerational transmission of reproductive behaviour in Botswana. The major source of data was the 2001 Botswana AIDS Impact Survey where a nationally representative random sample of men and women aged 10-64 years was selected using a stratified two-stage probability sample design. Covariates in the analysis include age, education, marital status, religion, age at first birth, residence, duration at residence and contraceptive use. The main analytical technique is linear regression. The results indicate that the reproductive behaviour of older generations has a significantly positive influence on the reproductive behaviour of the subsequent generation, but does not affect the subsequent generation homogeneously. The effect appeared much stronger for women who initiated childbearing at an older age, for women who had never been to school, and for the cohort aged 50-59 years. These findings suggest that number of siblings, as a reproductive behaviour determinant, may very well have confounded previous reproductive behaviour analyses in Botswana. The study draws attention to the importance of the effect of origin family size in determining reproductive behaviour outcomes in Botswana.

Does pregnancy induce the shedding of premalignant ovarian cells?

BACKGROUND

High parity is associated with reduced risk of ovarian cancer. One hypothesis is that pregnancy is associated with clearance of a fraction of the genetically modified (premalignant) cells from the ovaries.

METHODS

We evaluated this hypothesis using a model that estimates the cell clearance fraction at first and second pregnancy according to age at pregnancy. The model was fitted using reproductive history data from a cohort of 1.5 million Danish women born between 1935 and 1978 and followed for 28.7 million person-years. During this follow-up period, 2,035 developed invasive ovarian cancer.

RESULTS

We found the model to have a satisfactory fit despite the very few parameters involved. The model estimated similar cell clearance fractions for the first and second pregnancy and decreasing clearance with later age at pregnancy.

CONCLUSION

The relation of pregnancy history to risk of ovarian cancer can be well described by a cell clearance model that allows the cell clearance fraction to decrease with age at pregnancy.