title: Prediction of fecundability from semen analysis: problems in providing an accurate prognosis.
abstract: Information from semen analysis is used to predict the likelihood that a couple will conceive within a period of time. It is only possible to provide a probability; there can be no certainty. The probability is influenced by a host of factors including semen quality, and studies in large groups or using simple models are required to overcome this. Delayed conception from natural intercourse or poor fertilization at IVF has limited predictive power for a subsequent attempt. The problem is made worse by variations in sperm parameters among different ejaculates from the same man and by differences among groups of patients. Results of studies of potential criteria should be presented in a way that allows the effect of the test result on the probability of conception to be appreciated, and results should be confirmed on independent data sets. When there is potential for fertility, estimation of fecundability can only be approximate; however, progress is possible. Effects of semen quality can be clearly identified in large groups, and computer assisted semen analysis measurements do provide useful additional information for the success of intracervical insemination.
authors.affiliation: University Division of Obstetrics and Gynaecology, St Michael's Hospital, Bristol BS2 8EG, UK.
authors.forename: W. Chris L.
authors.initials: WC
authors.lastname: Ford