Personal hormone monitoring for contraception.
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.