Personal hormone monitoring for contraception

Abstract

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.

PIP: A newly developed personal system of hormone monitoring allows the rapid assay of estrone-3-glucuronide (EG) and luteinizing hormone (LH) in urine to determine the fertile period. The Persona system consists of disposable test sticks to measure EG and LH concentrations in early morning urine and a hand-held monitor that indicates by the use of red and green lights the fertile and infertile phases of the cycle. The monitor stores information for the previous 6 cycles and adapts to the individual user's patterns. The effectiveness of this regimen when used with abstinence during the identified fertile period was investigated in a prospective population-based study conducted in the UK, Ireland, and Germany. 710 women (median age, 30 years) with regular menstrual cycles were enrolled. The continuation rate after 13 cycles was 78%. 162 pregnancies occurred in 7209 cycles of use, 67 of which were method-related. The 13-cycle life-table method pregnancy rate was 12.1% (95% confidence interval (CI), 9.3-14.8%). As a result of these findings, the algorithm was changed to increase the median warning of the LH surge from 4 to 6 days. Had this revised algorithm been used, the method pregnancy rate would have been reduced to 6.2% (95% CI, 4.2-8.3%) and method efficacy increased to 93.8%. The total efficacy rate compares favorably with pregnancy rates in women using other nonhormonal methods of fertility control. Women with cycle lengths of 23-35 days can expect to be required to abstain from intercourse for 6-12 days each cycle.