Published in: European Journal of Obstetrics & Gynecology and Reproductive Biology

Objective: Some methods of family planning may occasionally work after fertilization or implantation. These effects may be important to some women. We explored Spanish women’s attitudes towards these potential mechanisms of action of family planning methods. Study design: Cross-sectional study in a Spanish representative sample of 848 potentially fertile women, aged 18-49. Data were collected using a 30-item questionnaire about family planning. Logistic regression was used to identify variables associated with women’s attitudes towards postfertilization effects. Results: The majority of women were married, held an academic degree and had at least one child. Forty-five percent of women would not consider using a method that may work after fertilization and 57 % would not consider using one that may work after implantation. Forty-eight percent of the sample would stop using a method if they learned that it sometimes works after fertilization, increasing to 63 % when referring to a method that sometimes works after implantation. Women who believe that human life begins at fertilization, those who believe it is important to distinguish between spontaneous and induced embryo losses and women wh