There is surprising evidence that the number of unwanted pregnancies ending in abortions has held relatively constant in France for the past twenty years, notwithstanding the spread of modern contraceptive methods which can be assumed to be highly effective. We first review the circumstances of modern contraceptive prevalence, then attempt to identify whether it has been consistent across all social status groups. We shall also examine whether some women are not contracepting despite having no desire for pregnancy. Only women capable of having experienced unwanted pregnancy are considered: this therefore excludes women who are sterile or sterilized, pregnant or seeking pregnancy, and without a sexual partner; all these categories are constant over time, and account in all for between 25% and 30% of women aged 20-44.