Personal hormone monitoring for contraception.

OBJECTIVE

To determine the effectiveness and acceptability of personal hormone monitoring for contraception.

DESIGN

A large prospective study was carried out on personal hormone monitoring for contraception when used with abstinence during the identified fertile days.

SETTING

Three country study under the auspices of the departments of Obstetrics and Gynaecology of the Universities of Birmingham, Dublin and Dusseldorf

SUBJECTS

Seven hundred and ten women, median age 30, were recruited from the 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 the fertile days which were displayed by a red light.

OUTCOME MEASURES AND RESULTS

One hundred and sixty two pregnancies occurred in 7209 cycles of use, of which 67 were method related pregnancies. The 13 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 algorithm 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 cent (4.2-8.3) and method efficacy of 93.8 per cent. The continuation rate after 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.