We estimated cholinesterase (EC 3.1.1.8) activities in erthrocytes and plasma of 443 men, 188 women not taking oral contraceptives, and 70 women who were taking oral contraceptives. Men in the first six decades of life had higher plasma cholinesterase activity than did women who were not taking oral contraceptives, and these women had higher plasma cholinesterase activity than women taking oral...

 Some cancers depend on naturally occurring sex hormones for their development and growth. Researchers are interested in learning whether the hormones in oral contraceptives affect cancer risk in women (see Question 1).  Some studies have shown an increased risk of breast cancer in women taking oral contraceptives, while other studies have shown no change in risk (see Question 2).  Oral cont...

Fragile X premutations are known to be a risk factor for diminished ovarian function at a relatively young age. We studied endocrine profiles of female fragile X family members (n = 79) at risk of premature ovarian failure (POF). Of these 79 women aged <40 years, 45 had menstrual cycles, and 34 were using oral contraceptives. Of the women with menstrual cycles, the premutation carriers had high...

1. There are conflicting reports regarding the effect of oral contraceptives on serum and erythrocyte folate concentrations and on folate absorption. A detailed study of this problem was therefore undertaken. 2. It was first ascertained that there was no significant variation in serum folate concentrations at different stages in the normal menstrual cycle. 3. No significant difference was found...

The incidence of ovarian neoplasms and functional ovarian cysts diagnosed at laparotomy or laparoscopy among the 17,000 women taking part in the Oxford Family Planning Association contraceptive study was investigated. Epithelial cancer of the ovary was only 25% as common among those who had ever taken oral contraceptives as those who had never done so (95% confidence interval 8% to 67%). There ...