<p>Provided are a method and a system for enabling highly accurate estimation of LH surge peak time and ovulation time at the early stage. A method which comprises: collecting urine samples of a single subject at intervals of 24 hours during a single menstruation cycle; determining luteinizing hormone (LH) in the samples to give LH concentrations (quantitative values) (a diamond plot); at the point (48 hours of the sampling) when the LH concentration exceeds a predetermined LH concentration threshold (60 mlU/ml), fitting a predetermined LH concentration time-change function (Gauss distribution) for the LH concentrations (quantitative values) obtained until that point (three diamond plots indicated by the arrows) using the least squares method; estimating the peak time of the function after the fitting as the LH surge peak time (69 hours of the sampling); and estimating the ovulation time based on the LH surge peak time. The dotted line indicates the correct LH surge peak time (75 hours of the sampling).</p>
