OBJECTIVE

To describe the characteristics and determinants of initiation of use of progestagens alone - i.e. without concomitant use of estrogen - among French premenopausal women.

METHODS

Forty-one thousand six hundred and three women from the French E3N cohort were included in our analyses. Prevalence of use was calculated from 1992 to 2005. Determinants of progestagens alone initiation were investigated prospectively from 1992 to 2005, using multivariable Cox proportional hazards models.

RESULTS

Fifty-eight per cent of women who had reached menopause between 1992 and 2005 ever used progestagens alone during their premenopause. Between 1992 and the end of 1990s, the increase in the prevalence of progestagens alone use in our cohort was close to 50%. Initiation of progestagens alone was significantly associated with a high level of education (postgraduate compared to high-school graduate: Hazard ratio [HR]: 1.09 95% confidence interval [CI]: 1.01-1.18), with a normal body mass index (overweight and obese women compared to normal-weight women: HR=0.84, 95% CI: 0.79-0.90 and HR=0.79, 95% CI: 0.69-0.89 respectively), history of gynecological disorders (mastalgia, benign breast disease and benign uterine or ovarian disease [HR=1.38, 95% CI: 1.27-1.49, HR=1.18, 95% CI: 1.13-1.24 and HR=1.60, 95% CI: 1.52-1.68 respectively]) and with recent gynaecological screening (as measured by recently performed mammogram or Pap smear HR=1.11, 95% CI: 1.05-1.17 and HR=1.38, 95% CI: 1.27-1.49 respectively).

CONCLUSIONS

Since, at least in France, use of progestagens alone at premenopause is common, evaluation of its risks and benefits is of public health importance.