An estimate of the natural fecundability ratio curve

Abstract

A curve of age‐specific fecundability ratio (to the level at age 20–24) is estimated. The rising part of the curve is estimated from Taiwanese data of the first conception delay according to the harmonic mean method; the declining part, from Hutterite data according to a proposed model of marital fertility rate. Heterogeneous fecundabilities and homogeneous aging effect among women in each age group are assumed. The estimated declining path of fecundability is found to be different from that of the fertility rate.