Childbearing and mortality from cancer of the corpus uteri.

BACKGROUND

To investigate the mortality from cancer of the corpus uteri in relation to parity and age at first and last birth.

METHODS

A cohort of 431,604 married women aged 45-74 years at the Norwegian Census in 1970 was followed over 15 years. A total of 752 deaths from cancer of the corpus uteri were diagnosed during follow-up.

RESULTS

All age groups showed significant trends of decreasing mortality rates with increasing number of children. The age-adjusted reduction in mortality was 9.2% (95% CI 5.2-13.0) for each child. Women with 8-11 children had a relative risk of 0.35 (95% CI 0.14-0.85) compared to nulliparous women. For first birth at age > = 35 years versus < = 19 years, the relative risk was 0.53 (95% CI 0.34-0.83). No significant effect of age at last birth was found.

CONCLUSIONS

This study supports the notion that high parity and postponing the first delivery may reduce the risk of uterine cancer death.