Contraceptive behaviour and fertility patterns in an inner London group practice.

458 of 600 questionnaires handed out to women aged 17 to 40 attending the surgery for contraceptive advice were completed, a take-up rate of 76%. The survey revealed a relatively high proportion of young IUD users (15% compared with national figures of approximately 5%). It also showed that the population used contraception reasonable effectively. The proportion of unplanned pregnancies (58%) represented a true contraceptive failure rate of 2.5/100 women-years. 50% of all unplanned pregnancies and 29% of all conceptions ended as terminations. The most common contraceptive first choice was the pill. Contraception was not considered by many younger women until they realized they were pregnant. The findings are applicable only within the practice, and cannot be applied to society in general. Research problems encountered during the study are responder compliance, need for control data, difficulties in interpretation of skewed figures, problems of analyzing subjective data, multi-observer studies, and observer bias.