Cross-sectional length-biased data arise from questions on the at-risk time for an event of interest from those who are at-risk but have yet to experience the event. For example, in the National Survey on Family Growth (NSFG), women who wer…
Study questionHas there been there a temporal change in time-to-pregnancy (TTP) in the USA.Summary answerOverall, TTP was stable over time, but a longer TTP for women over 30 and parous women was identified.What is known alreadyFertility ra…
ObjectiveTo estimate the prevalence of infertility using a current duration approach for comparison with a traditional constructed measure.DesignCross-sectional survey.SettingNot applicable.Patient(s)A nationally representative sample of fe…
An evolving body of evidence suggests an adverse relation between persistent organochlorine pollutants (POPs) and menstruation, though prospective longitudinal measurement of menses is limited and served as the impetus for study. We prospec…