Does Pregnancy Protect Against Ovarian Cancer?

A prospective study of urinary androgen levels and ovarian cancer

“…Recent studies have indicated that many of the reproductive factors related to the risk of breast cancer also exert a qualitatively similar influence on cancer of the ovary. Factors implicated in the aetiology of both diseases include nulliparity or low parity (Joly et al, 1974;Newhouse et al, 1977;Beral ef al., 1978;Annegers et al, 1979;Hildreth et al, 1981;Franceschi et al, 1982), late age at first birth (Joly et al, 1974;Newhouse et al, 1977;Beral et al, 1978;Annegers et al, 1979;Hildreth et al, 1981;Franceschi et al, 1982), early menarche (Franceschi et al, 1982), late menopause (Hildreth et al, 1981;Franceschi et al, 1982), and total ovulatory years (Fathalla, 1971;Annegers et al, 1979;Casagrande el al., 1979). Use of oral contraceptives reduces the risk of both ovarian cancer (Newhouse et al, 1977;Hildreth et al, 1981;Casagrande et al, 1979) and benign breast disease (Vessey et al, 1979;Ernster, 1981), but appears to have little overall influence on the risk of breast cancer (Vessey et al, 1979;Kelsey, 1979).…”

“…Use of oral contraceptives reduces the risk of both ovarian cancer (Newhouse et al, 1977;Hildreth et al, 1981;Casagrande et al, 1979) and benign breast disease (Vessey et al, 1979;Ernster, 1981), but appears to have little overall influence on the risk of breast cancer (Vessey et al, 1979;Kelsey, 1979). Postmenopausal oestrogen administration may slightly increase the risk of breast cancer and of ovarian cancer (Beral, 1978;Kelsey, 1979;Weiss et al, 1982). These observations clearly implicate one or more of the hormones which regulate reproductive function as important aetiological factors for both of these cancers.…”

The epidemiology of epithelial ovarian cancer: a review

“…Different birth cohorts of women in Britain, Sweden and the US show varying rates of ovarian cancer. Incidence rises among successive cohorts born during the late nineteenth century, with peaks among those born in 1906 (in Britian) and 1925-1929 (in Britain, Sweden and the US) and declining thereafter (16)(17)(18) . Similar incidence patterns have also been observed in Denmark, although the peak in the earlier part of this century was not apparent (19) .…”

“…Studies in Britain and China have found an elevated risk of ovarian cancer among women of higher socioeconomic status (21)(22)(23) . This relationship is believed to be the result of lower fertility rates among these more educated and affluent groups (18) . However, few studies have investigated the effect of social class while accounting for the effects of parity.…”

Current management of epithelial ovarian carcinoma: A review

“…There is evidence to suggest that in the latter half of the century the incidence in Western countries may have stabilized, possibly as a result of oral contraceptive use [4]. It is clear that what Fathalla [5] termed "incessant ovulation" plays a role, and the protective effect of pregnancy, first demonstrated by Beral and colleagues in 1978 [6] is paralleled by the effects of oral contraception [7]. About 5% of cases of ovarian cancer are related to inherited genetic abnormalities [8].…”