Personal hormone monitoring for contraception

Objective: To determine the effectiveness and acceptability of personal hor mone monitoring for contraception. Design. A large prospective study was carried out on personal hormone monit oring for contraception when used with abstinence during the identified fer tile days. Setting. Three country study under the auspices of the departments of Obste trics and Gynaecology of the Universities of Birmingham, Dublin and Dusseld orf. Subjects. Seven hundred and ten women, median age 30, were recruited from t he general population. They were required to have regular menstrual cycles (23-35 days) and to be delaying their next pregnancy. Interventions. Personal hormone monitoring consists of a hand held monitor and disposable test sticks which measure changes in urinary concentrations of oestrone-3-glucuronide and luteinising hormone. An algorithm estimated t he fertile days which were displayed by a red light. Outcome measures and results. One hundred and sixty two pregnancies occurre d in 7209 cycles of use, of which 67 were method related pregnancies. The 1 3 cycle life-table method pregnancy rate (95 per cent CI) was 12.1 per cent (9.3-14.8). The system allowed analysis of the effect of changes to the al gorithm to modify the defined fertile period As a result the algorithm was changed to increase the median warning of the luteinising hormone surge to six days. With the revised algorithm, half of the method pregnancies would have been prevented giving a calculated method pregnancy rate of 6.2 per ce nt (4.2-8.3) and method efficacy of 93.8 per cent. The continuation rate af ter 13 cycles was 78 per cent. Conclusion. Personal hormone monitoring proved simple to use and will be of value to women who do not want to use other methods of contraception.