Study of Time to Pregnancy in Normal Fertility

Research has established that there are relatively few days of the menstrual cycle that have a substantial probability of pregnancy from coitus, and that there are prospective biomarkers that allow a woman or couple to identify these "fertile" days. However, it remains unclear how this knowledge may improve a couple's chances of conceiving. All couples participating in this study must have a history of previous pregnancy together and no history suggesting subfertility. Participants in this study will be randomly assigned to one of two groups. One group will receive instruction about identifying the days when a woman is mostly likely to get pregnant from intercourse, using the Creighton Model FertilityCare System, and the other group will receive instructions about the menstrual cycle, fertility, and preparing for pregnancy. Randomization is stratified by age. All participants will keep a daily fertility chart and use a computerized device called the Fertility Monitor with urine dipsticks to monitor hormones of the menstrual cycle. The primary outcome is time to pregnancy.